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AUTOMOTIVE  TRADE 
TRAINING 


AUTOMOTIVE 
TRADE  TRAINING 


RAY  F.  KUNS 

Principal  Automotive  Trade  School 
Cincinnati,  Ohio 


BRUCE-  MILWAUKEE 


THE  BRUCE  PUBLISHING  COMPANY 
MILWAUKEE.  WISCONSiN 


Copyright  1922 
THE  BRUCE  PUBLISHING  COMPANY 


Printed  in  the  United  States 
of  America 


INTRODUCTION 

As  may  be  gathered  from  its  title,  this  book  has  been  worked 
out  with  one  main  idea  in  mind,  namely,  to  present  a  clear-cut  and 
concise  explanation  of  the  automotive-trades  theory  and  practice, 
to  all  who  are  seeking  information  m  this  field.  Another  purpose 
hardly  less  important  was  to  bring  all  this  desirable  information 
under  one  cover.  Just  as  the  mechanic  must  work  with  the  tools  at 
hand,  he  is  very  often  required  to  do  the  job  with  the  information 
at  hand  The  various  trades  are  so  interrelated  that  it  has  not  seemed 
wise  to  try  to  treat  each  one  separately. 

The  automotive  trades  vary  widely  in  content.  The  automobile 
repair  man  makes  the  usual  repairs  and  installs  the  new  parts  neces- 
sary to  the  machinery  of  the  automobile.  The  automotive  electrician 
handles  the  repairs  and  new  installation  of  the  electrical  equipment. 
The  storage  battery  man  recharges  and  repairs  the  battery  equip- 
ment. The  vulcanizer  installs  new  and  repairs  old  tire  equipment 
The  radiator  repair  man  cares  for  the  radiator  and  other  sheet  metal 
repairs.  Other  phases  of  the  automotive  trades  work  are  likewise 
special  fields. 

However,  it  is  frequently  the  case  that  one  concern  or  even  one 
man  will  be  found  doing  all  varieties  or  several  combinations  of 
automotive  trades  work.  The  owner  is  frequently  desirous  of  doing 
the  repair  work  on  his  car.  With  these  facts  in  mind  the  author  has 
attempted  to  organize  the  vast  amount  of  information  and  to  arrange 
the  essential  processes  so  as  to  give  correct  trade  practice. 

Correct  trade  practice  is  very  largely  a  fixed  matter.  Not  all 
mechanics  use  the  same  methods,  but  the  results  arrived  at  must 
not  vary.  For  this  reason  the  theory  of  design  and  the  construction 
of  the  parts  or  units  under  repair  must  be  understood.  Repairs  must 
be  carefully  made  in  order  to  be  right.  The  author  is  not  particularly 
concerned  as  to  whether  the  repairs  are  made  by  the  owner  of  the 
car,  or  by  the  repair  man  to  whom  the  owner  has  entrusted  the  work. 
His  concern  is  rather  in  helping  each  to  do  the  work  in  a  manner 
which  will  result  in  a  safe,  satisfactory  and  permanent  job.  In  other 
words,  this  volume  is  dedicated  to  the  teaching  of  high  standards  of 
-workmanship. 

No  attempt  has  been  made  to  show  methods  of  repair  and  over- 
haul on  every  make  of  automobile,  but  every  type  of  equipment  has 
been  treated.  The  description  of  design  and  operation  is  given  in  the 
first  part  of  each  chapter  and  the  usual  line  of  repair  work  for  that 
type  of  equipment  appears  in  the  latter  part  of  the  chapter.  To  learn 
what  information  is  available  on  any  type  of  equipment,  the  index 
should  be  consulted  with  reference  to  both  job  sheets  and  general 
information. 


The  author  is  desirous  of  acknowledging  the  splendid  help  re- 
ceived from  his  associates  on  the  faculty  of  the  Cincinnati  Automotive 
Trade  School.  Each  one  deserves  commendation  for  his  help  in  his 
own  particular  line:  Mr.  E.  O.  Bathgate  on  chassis;  Messrs.  Frank 
Buerkle  and  William  Schatz  on  engines ;  Mr.  Frank  Bechtold  on 
service ;  Mr.  Fred  Schuster  on  battery  work ;  Mr.  Chas.  Shields  on 
vulcanizing;  Messrs.  Floyd  E.  Hauss,  Roy  E.  Cahall,  Fred  Schaeper- 
klaus  and  Walter  von  Schlichten  on  starting,  lighting  and  ignition. 

Acknowledgment  is  also  due  to  the  following  manufacturers  of 
automotive  apparatus  and  equipment  for  their  splendid  co-operation: 


Akron-Williams  Co.,  Akron,  O. 

The  Allen  Motor  Car  Company,  Columbus, 
Ohio. 

American  Bosch  Magneto  Corp.,  Detroit, 
Mich. 

Apperson  Bros.  Automobile  Co.,  Kokomo, 
Ind. 

Atwater  Kent  Manufacturing  Co.,  Philadel- 
phia,  Pa. 

The  Borg  &  Beck  Co.,  Chicago,  111. 

The  Buda  Co.,  Harvey,  111. 

Buffalo  Forge  Co.,  Buffalo,  N.  Y. 

Buick  Motor  Co.,  Flint,  Mich. 

Byrne,  Kingston  &  Co.,  Kokomo,  Ind. 

Cadillac  Motor  Car  Co.,  Detroit,  Mich. 

Chandler  Motor  Car  Co.,  Cleveland,  Ohio 

Cincinnati  Storage  Battery  Co.,  Cincinnati, 
Ohio. 

Cole  Motor  Car  Co.,  Indianapolis,  Ind. 

Connecticut  Telephone  &  Electric  Co.,  Meri- 
den,   Conn. 

Continental  Motors  Corp.,  Detroit,  Mich. 

Dodge  Bros.,  Detroit,   Mich. 

Eisemann  Magneto  Corp.,  Brooklyn,  N.  Y. 

Dyneto  Electric  Corp.,   Syracuse,  N.  Y. 

The  Electric  Storage  Battery  Co.,  Philadel- 
phia,  Pa. 

Essex   Motors,    Detroit,    Mich. 

Ford  Motor  Co.,  Detroit,  Mich. 

Franklin  Automobile  Co.,  Syracuse,  N.  Y. 

Gemmer  Manufacturing  Co.,   Detroit,   Mich. 

General  Electric  Co.,  Schenectady,  N.  Y. 

The  Goodyear  Tire  &  Rubber  Co.,  Akron, 
Ohio. 

Gray  &  Davis,  Inc.,  Boston,  Mass. 

Greenfield  Tap  &  Die  Corp.,  Greenfield,  Mass. 

The   Haynes  Automobile  Co.,   Kokomo,   Ind. 

Hudson  Motor  Car  Co.,   Detroit,   Mich. 

The  K-V/  Ignition  Co.,  Cleveland,  Ohio. 

The  Kelly-Springfield  Motor  Truck  Co., 
Springfield.  Ohio. 

King  Motor  Car  Co.,  Detroit,  Mich. 

The  Leece-Neville  Co.,  Cleveland,  Ohio. 

The  Lavine  Gear  Co.,  Milwaukee,  Wis. 

Maxwell  Motor  Sales  Corp.,  Detroit,  Mich. 

The  Nash  Motors  Co.,  Kenosha,   Wis. 


National  Lamp  Works,  Cleveland,  Ohio. 

National  Motor  Car  &  Vehicle  Corp.,  In- 
dianapolis, Ind. 

Nordyke  &  Marmon   Co.,   Indianapolis,    Ind. 

North  East  Electric  Co.,  Rochester.  N.  Y. 

Oakland  Motor  Car  Co.,  Pontiac,  Mich. 

Oxweld-Acetylene  Co.,  Chicago,  111. 

Packard  Motor  Car  Co.,  Detroit,  Mich. 

The  Park  Drop  Forge  Co.,  Cleveland,  Ohio. 

The  Peerless  Motor  Car  Co.,  Cleveland,  Ohio. 

The  Pierce-Arrow  Motor  Car  Co.,  Buffalo, 
N.  Y. 

The  Pierce  Governor  Co.,  Anderson,  Ind. 

Remy  Electric  Div.,  General  Motors  Co., 
Anderson,    Ind. 

Reo   Motor  Car  Co.,  Lansing,  Mich. 

Republic  Motor  Truck  Co.,  Alma,  Mich. 

Rochester  Motors  Co.,  Inc.,  Rochester,  N.  Y. 

Ross  Gear  &  Tool  Co.,  Lafayette,  Ind. 

The  Simms  Magneto  Co.,  East  Orange,  N.  J. 

Splitdorf  Electrical  Co.,   Newark,   N.  J. 

Standard  Steel  Car  Co.,  Pittsburgh,  Pa. 

Stearns-Knight  Motor  Car  Co.,  Cleveland, 
Ohio. 

Stromberg  Motor   Devices   Co.,   Chicago,   111. 

The  Studebaker  Corp.,  South  Bend,  Ind. 

Stutz  Motor  Car  Co.,   Indianapolis,   Ind. 

The  Tillotson  Manufacturing  Co.,  Toledo, 
Ohio. 

Thermoid  Rubber  Co.,  Trenton,  N.  J. 

The  Timken-Detroit  Axle  Co.,  Detroit,  Mich. 

Torbensen  Axle  Co.,  Cleveland,  Ohio. 

The  Timken  Roller  Bearing  Co.,  Canton, 
Ohio. 

Wagner  Electric  Mfg.  Co.,  St.  Louis,  Mo. 

Weaver  Mfg.  Co.,   Springfield,   111. 

Westinghouse  Electric  &  Mfg.  Co.,  Spring- 
field,  Mass. 

Weston  Electrical  Instrument  Co.,  Newark, 
N.  J. 

The  Wheeler-Schebler  Carburetor  Co.,  In- 
dianapolis, Ind. 

Willard  Storage  Battery  Co.,  Cleveland, 
Ohio. 

Willys-Overland,  Inc.,  Toledo,  Ohio. 

The  Zenith  Carburetor  Co.,  Detroit,  Mich. 


TABLE  OF  CONTENTS 


CHAPTER  1 

PAGE 

FRAMES  AND  SPRINGS— Frames— Springs— Radius  Rods— Hotch- 
kiss  Drive— Springs;  Quarter  Elliptic.  Semi-Elliptic,    Three-quarter 

Elliptic,   Full   Elliptic.   Cantilever " 9-19 

JOBS— 1— Tightening  Spring  Clips.  2— Adjusting  Shackle  Bolt.  3— 
Lubricating   Spring  Shackles.     4— Graphiting  Spring  Leaves.     5— 

Spring   Overhaul.     6 — Straightening    Car    Frame 14-9 

CHAPTER  2 
STEERING    GEARS    AND    FRONT    AXLES— Planetary    Steering 
Gear— Worm    and    Gear— Worm    and    Sector— Screw    and    Nut- 
Pinion  and  Sector — Front  Axle  Types — Axle  Repair  Work — Front 
Axle      Design  —  Camber  —  Toe-In  —  Castering      Effect  —  Steering 

Knuckle   Arm   Design 20-39 

JOBS — 7 — Testing  and  Re-Aligning  Front  Wheels.  8 — Overhaul  Ford 
Front  Radius  Rod.  9 — Overhaul  Ford  Front  Wheels  and  Bearings. 
10 — Tightening  Up  Ford  Steering  Gear.  11 — Overhauling  and  Re- 
bushing  Ford  Front  Axle.  12 — Ford  Steering  Wheel  Inspection 
and  Lubrication.  13 — Adjusting  and  Lubricating  Timken  Front 
Wheel  Bearings.  14 — Replacing  Front  Wheel  Spindle  Cones  or 
Races.  15 — Replacing  Wheel  Bearing  Cups.  16 — Straightening 
Damaged  Front  Axles.  17 — Replacing  Steering  Knuckle  Body. 
18 — Steering     Gear     Lubrication.     19 — Adjusting    Steering     Gears. 

20 — Overhauling   Drag  Link 30-9 

CHAPTER  3 
REAR  AXLES  AND  BRAKES— Live  Axles— Plain  Live— Floating: 
Semi,  Three-quarter,  Full — Live  Axle  Types  of  Drive — Bevel  Gear 
and  Pinion — Worm  and  Gear — Single  Chain  Drive — Dead  Axle 
Drive — Internal  Gear  Drive — Double  Reduction  Gears — Differen- 
tial Construction — Rear  Axle  Trouble — Brakes:  Braking  Surface, 
Types    of — Double    Width    Drum — Transmission — Brake    Shoes — 

Brake    Names — Brake    Equalizers 40-72 

JOBS — 21 — Adjusting  External  Brake  Bands.  22— Adjusting  Internal 
Expanding  Brakes.  23 — Removing  Grease  and  Oil  from  Brakes. 
24— Relining  Brakes.  25— Squeaking  Brakes.  26— Adjusting 
Packard  Twin  Six  Foot  Brakes.  27— Adjusting  Packard  Twin 
Six  Hand  Brakes.  28— Split  Housing  Type  Rear  Axle  Over- 
haul. 29— Overhauling  Rear  Axles  of  Single  Piece  Housing 
Construction.  30— Pulling  Rear  Wheels.  31— Adjusting  Rear  Axle 
Bevel  and  Pinion  Gears.  32 — Remove  Ford  Rear  Axle  from  Car. 
33— Removing  Universal  from  Axle.  34— Disassembling  Ford  Rear 
Axle.     34-a— Disassembling  Ford  Axle  Differential  Inspection  and 

Reassembly    ^^''^^ 

CHAPTER  4 
CLUTCHES  TRANSMISSIONS  AND  UNIVERSALS— Transmis- 
sion Units— Progressive— Friction  Disk— Progressive  Selective— 
Selective— Gear  Ratio— Reverse  Gear— Special  Transmission  Types 
—Transmission  Troubles— Planetary  Type  Transmission— High 
Speed— Slow  Speed— Reverse— Planetary  Principle  Explained— 
Speed:  Slow— Reverse— High— Clutches:  Types  of.  Cone,  Plate, 
Disk.  Grease  and  Oil  Soaked— Neatsfoot  Oil— Clutches:  Grabbing 
Slipping,  Wet— Universal  Joints:  Mechanical  Principle— Angle  of 
Drive— Type  of  Universals— Slip  Joint— Fabric  Unversals— Slip  ^^^^^^ 
Joint  Unnecessary   


Table  of  Contents — Continued 

PAGE 

JOBS — 35 — Removing  Transmission  Bands.  36 — Relining  Ford  Trans- 
mission Bands.  37— Adjusting  Clutch  on  the  Ford  Car.  38— Over- 
hauling Ford  Transmission.  39 — Standard  Selective  Type  ot  Trans- 
mission Overhaul.  40 — Standard  Selective  Type  Transmission  Care. 
41 — Cleaning  and  Oiling  an  Exposed  Cone  Clutch.  42 — Applying  a 
New  Lining  to  a  Cone  Type  Clutch.  43 — Relining  a  Disk  or  Plate 
Clutch.  44 — Adjusting  a  Borg  and  Beck  Type  Clutch.  45 — Clutch 
Collar  Care.     46 — Universal  Joint  Lubrication.     47 — Universal  Joint 

Overhaul    31-101 

CHAPTER  5 

POWER  GENERATION  AND  POWER  PLANTS,  ENGINES— 
Power  Generation — Names  and  Location  of  Engine  Parts — Opera- 

tion: — Four  Stroke  Cycle — Cycles  Completed  per  Minute 102-113 

CHAPTER  6 

FUNCTIONS  OF  ENGINE  PARTS,  TROUBLES  AND  REPAIRS 
— Crank  Case — Cylinder  Blocks  and  Cylinders — Engine  Types — 
Cylinder  Heads — Cylinder  Care  and  Repair — Scored  Cylinders — 
Frozen  or  Bursted  Cylinders  and  Cylinder  Heads — Crank  Shafts: 
V  Type  Engines,  Right  and  Left  Hand,  Six  Cylinder  Firing  Order 
— Crank  Shaft  Troubles — Main  Engine  Bearings:  Burned,  Taking 
Up  Main,  Scraping  in  Main — Pistons — Material  and  Construction: 
Piston — Piston  Clearance  Allowance — Piston  Rings — Leak  Proof 
Rings — Pistons:  Pins,  Pin  Fit — Securing  the  Piston  Pin — Connect- 
ing Rods — Piston  Pin  Bearing — Rod  Bearings — Cam  Shaft — Two 
Valves  Per  Cylinder — Cam  Shaft  Drive — Valve  Lifters — Valves — 
Valve  Grinding — Rocker  Arms — Knight  Type  Engines — Valve 
Timing — Valve  Lap — Degrees  Converted  to  Inches 114-174 

JOBS — 48 — Fitting  or  Taking  Up  Connecting  Rod  Bearings.  49 — 
Scraping  Connecting  Rod  Bearings.  50 — Fitting  or  Taking  Up 
Main  Engine  Bearings.  51 — Scraping  Main  Engine  Bearings. 
52 — Polishing  a  Crank  Shaft.  53 — Removing  a  Piston  Pin  of  the 
Clamp  Type.  53-a — Removing  a  Piston  Pin  Where  the  Bushing 
is  in  the  Rod.  54 — Removing  Piston  Pin  Bushing  from  Piston. 
55 — Fitting  Main  Engine  or  Crank  Shaft  Bearings  on  Ford  En- 
gine. 56 — Removing  Engine  from  Ford  Car.  57 — Adjusting  Con- 
necting Rod  Bearings  on  Ford  Engine.  58 — Adjusting  Valve  Tap- 
pets. 59 — Methods  of  Removing  Valves.  60 — Cleaning  Valves. 
61 — Grinding  Valves.  62 — Reseating  Valves.  63 — Timing  Engines. 
64 — Silent  Chain  Care.  65 — Removing  a  Cylinder  Head.  66 — 
Replacing  a  Cylinder  Head.  67 — Shellacing  a  Cylinder  Head  to 
Prevent  Compression  Leaks.     68 — Fitting  New  Piston  Rings.     69 — 

Fitting  New  Pistons.     70 — Scraping  Out  Carbon 147-174 

CHAPTER  7 

OILING  SYSTEMS  — Full  Splash  — The  Splash  and  Circulating- 
Forced  Feed — Oil  Pumps — Centrifugal  or  Rotating  Vane  Pump — 
Gear  Pump — Plunger  Type  Pump — Indicating  Devices — Sight  Feed 
— Pressure  Gauge — Caring  for  Oiling  Systems — Oil  Wears  Out — 
Draining  Oil — Troubles  Due  to  Loss  of  Lubricating  Qualities 175-192 

JOBS — 71 — Cleaning  Valve  Stems  and  Guides  and  Piston  Rings.  72 — 
General  Instructions  for  Draining,  Flushing  and  Refilling  the  En- 
gine Crank  Case.     73 — Draining  Oil  From  Packard  Engine.     74 — 

Draining  Oil  from  Hudson  Engine.     75 — Cleaning  an  Oil  Pan 189-192 

CHAPTER  8 

COOLING  SYSTEMS— Air:  Direct,  Indirect— Water  Cooling— Ther- 
mosiphon — Forced   or   Pump   Circulation — Cooling  System   Care — 


Table  of  Contents — Continued 

PAGE 
Radiator  Hose  —  Rubber  Hose  Troubles  —  Steaming  Radiator — 
Radiator  Mountings — Radiator  Types — Tubular  Type — Honeycomb 
or  Cellular  Type — Radiator  Troubles — Types  of  Pumps — Pump 
Drive — Pump  Troubles — Impeller  Troubles — Cooling  Fans — Fans: 
Care,  Belt,  Belt  Adjusting — Changes  of  Temperature — Hood  and 
Radiator  Covers — Thermostat  Control — Cooling  Solutions — Non- 
Freezing  Solutions  Recommended  —  Overheated  Motors  —  Boyce 
Motometer — Recognizing  an  Overheated  Motor — Causes  of  Over- 
heating— Cooling  the  Overheated  Engine — Filling  an  Overheated 
Engine — Non-Leak  Solutions — Use  of  Cereal  Preparations — Use  of 

Liquid   Preparations — Cleaning  the   Radiators 193-212 

JOBS — 76 — Radiator  Hose  Care.  77 — Radiator  Care.  78 — Removing 
a  Radiator.  79 — Testing  a  Radiator  for  Leaks.  80 — Repairing  a 
Radiator  Leak  with  a  Liquid  Compound.  81 — Repairing  a  Radiator. 
82 — Overhauling  a  Water  Pump.     83 — Packing  a  Pump 208-213 

CHAPTER  9 

FUEL  SYSTEMS— GASOLINE  SYSTEMS— Gravity  System— Pres- 
sure Feed — Vacuum  Systems — Vacuum  Tank — Stewart  Vacuum 
Tank  Parts — Principles  of  Carburetion:  Liquids:  Evaporating,  Vola- 
tile— Heat — Vacuum — Spraying — Vaporization  and  Carburetion — 
Carburetor  Design — Mixture:  Explosive,  Rich,  Lean,  Correct — 
Power  —  Venturi  Tube  —  Nozzles  —  Gasoline  Level  —  Float  and 
Needle  Valve — Float  Troubles — Hot  Air  Stove — Hot  Spot  Mani- 
fold— Hot  Water  Heat — Exhaust  Gas  Jackets — Valves:  Choke, 
Air,  Adjusting  Air — Adjusting  Gasoline  Nozzle — Throttle — Meter- 
ing Pins — Dash  Pot — Fuel  Systems:  Plain  Tube  or  Compound 
Nozzle  Type,  Air-Bled  Jets 213-261 

JOBS — 84 — Maxwell  Carburetor.  85 — Packard  Twin  Six  Carburetor. 
86 — Tillotson  Carburetor.  87 — Buick  Carburetor.  88 — Kingston 
Carburetors — Models  E  and  L.  89 — Rayfield  Carburetor — Model 
L  L  3  P.  90— Zenith  Model  L  Plain  Tube  Compound  Nozzle. 
91— U.  S.  A.  Standard  Carburetor.  92— Cadillac  Carburetor.  93— 
Stromberg  Type  M.  Plain  Tube  Carburetors.  94 — The  Stromberg 
Economizer.  95 — Dodge  Carburetor.  96 — Ball  and  Ball  Carburetor 
on  King  Cars.  97 — Hudson  Supersix  Carburetor.  98 — Pierce 
Arrow  Carburetors.  99 — Schebler  Dash  Pot  Air  Valve  Type  Car- 
buretor.    100 — Carburetor    Jobs    231-261 

CHAPTER  10 

FUNDAMENTAL  ELECTRICAL  DATA— Fundamental  Principles 
— Source  of  Supply — Primary  Battery — Secondary  Battery — Mag- 
netic Lines  of  Force — Volts — Ampere — Ohm — Abbreviations  or 
Symbols — Rating  Electrical  Power — Conductors — Non-Conductors 
or  Insulators — Positive  and  Negative — Magnetism:  Producing, 
Residual — Electro  Magnets — Magnetic  Poles — Magnetic  Needle — 
Permanent  Magnets  —  Magnetizing  Steel  for  Permanency  —  The 
Molecular  Theory — Saturation — Flux — Current  Generation — Inter- 
nal Circuits — Induction — Armatures — Alternating  Current — Direct 
Current — Commutator — Field — Current  Control — Resistance  Units — 
Fuses — Ground — Terminals  and  Poles — Direction  of  Induced  Cur- 
rent— Solenoid — Condenser 262-285 

CHAPTER  11 

BATTERIES  AND  BATTERY  CARE— Battery:  Rating,  Wear- 
Battery   Construction:     Battery   Box — Cell   Jars — Element— Plates: 


Table  of  Contents — Continued 

PAGE 

Positive,  Negative — Active  Material — Forming  Plates — Separators 
— Cell  Covers — Sealing  Compound — Terminals  and  Straps — Bat- 
tery Care:  Distilled  Water — Battery  Freezing — Testing  Battery — 
Hydrometer  Reading — Battery  Charging  While  in  Service — How 
To  Recognize  Battery  Faults  and  Good  and  Damaged  Battery 
Parts:  Tests  Which  Indicate  the  Need  of  Opening  the  Battery — 
Sulphation  —  Overheated  Plates  —  Damaged  Separators  —  Frozen 
Plates — Judging  the  Value  of  Positive  Plates — of  Negative  Plates 

— of  Battery  Case — of  Jars  and  Jar  Covers 286-324 

JOBS — 101 — Opening  Batteries  for  Inspection  and  Repair,  102 — Open- 
ing Willard  Type  "Sjwn"  and  "Sjrn"  Battery.  103 — Reassem- 
bling the  Battery.  104 — Element  Repair  and  Inspection.  105 — 
Battery  Shop  Repair  Methods.  106 — Making  and  Using  a  Test 
Outfit  for  Reading  Voltage  of  Individual  Cells  with  Closed  Circuit. 
107 — Cadmium  Test.  108 — Grounded  Battery.  109 — Removing 
and  Resealing  Exide  Single  Cover  Type  Covers.  110 — Opening  Cin- 
cinnati Batteries.  Ill — Making  and  Using  Electrolyte.  112 — 
Charging  a  Repaired  Battery.  113 — Caring  for  Batteries  on  Charge. 
114 — Discharging  a  Battery.  115 — Caring  for  Batteries  in  Stor- 
age      300-324 

CHAPTER  12 

BATTERY  IGNITION— Battery  Ignition— Ignition  Coil— Principle 
of  Inducton  Coil — Air  Gap — Timer-Distributor — Spark  Control — 
Switches — Condensers — Spark  Timing — Vibration  Coil  Ignition: 
Principle  of  Vibrator — Timer — Timing  the  Spark 325-363 

JOBS— 116— Atwater  Kent  Ignition  System,  Type  CC.  117— Atwater 
Kent  Ignition  System  K-2.  118 — North  East  Ignition  System  for 
Dodge  Cars.  Model  O.  119 — Hudson  Delco  Ignition.  120 — 
Buick  Delco  Ignition.  121 — Pierce  Arrow  Double  Distributor. 
122 — Remy  Ignition.  123 — Connecticut  Ignition  System.  124 — 
Wagner  Ignition.  125 — Open  Circuit  in  the  Primary  of  the  Ignition 
Coil.  126 — Open  Circuit  in  the  Secondary  of  the  Ignition  Coil.  127 
— Open  Circuit  in  Ignition  Coils  with  Connected  Windings.  128 — 
Short  Circuit  in  the  Primary  of  the  Ignition  Coil.  129 — Short 
Circuit  in  the  Secondary  Winding  of  the  Ignition  Coil.  130 — 
Ground  Between  Primary  and  Secondary  Windings.  131 — 
Grounded   Condenser.     132 — Short   Circuited   Condenser 337-363 

CHAPTER  13 

MAGNETO  IGNITION— Magneto:  Low  Tension,  H  or  Shuttle  Type 
Low  Tension — Inductor  or  Stationary  Coil  Type — Magnets — Pole 
Shoes — Non-Magnetic  Metals — Armature — Slip  Rings — Breaker 
Points — Transformer  or  Step-Up  Coils — Contact  Points  in  Series — 
Shunt  Current  Interruption  Induction — Distributing  High  Tension 
Current  from  a  Low  Tension  Magneto — Timing  Spark  on  Low 
Tension  Magnetos — Dual  Ignition — Dual  Ignition  Switch — Push 
Button  Starting — Low  Frequency  Inductor  Type  Magnetos — No 
Brushes — High  Frequency  Inductor  Type  Magnetos — Method  of 
Generating — External  Circuit  on  Ford  Ignition — High  Tension 
Magnetos:  Types:  High  Tension  Armature — Low  Tension  Circuit 
in  Armature — High  Tension   Inductor 364-428 

JOBS — 133 — K-W  Low  Tension  Magneto  Generator.  134 — K-W  High 
Tension  Magneto.  135 — Simms  High  Tension  Magnetos.  136 — 
Bosch  Magnetos,  Du  Types.  137 — Bosch  High  Tension  Magneto 
B-4  and  B-6  Types.     138 — Bosch  High  Tension  Magnetos,  Types 


Table  of  Contents — Continued 

PAGE 
ZR-4  and  ZR-6.  139— Bosch  NU-4  High  Tension  Magneto.  140— 
Bosch  Dual  Ignition  Systems.  141 — Bosch .  Duplex  Ignition  Sys- 
tem. 142 — Bosch  Vibrating  Duplex  Ignition.  143 — Bosch  Adjust- 
able Impulse  Starter  Coupling.  144— Eisemann  High  Tension  Mag- 
neto G-4.  145 — Eisemann  Magneto  GA-4.  146 — Eisemann  Dual 
Ignition.  147 — Dixie  Magneto.  Aero  Models  448-449  and  648- 
649.  148 — Dixie  Magneto.  Models  46,  462  and  246.  149 — The 
Splitdorf  Impulse  Starter.  149A — Splitdorf  Adjustable  Magneto 
Coupling 379-428 

CHAPTER  14 

STARTING  MOTORS  AND  GENERATORS— Division  of  Duties- 
Regulating  Generator  Output — Inserted  Resistance  or  Vibrating 
Relay  Controller — Differential  Compound  Wound  or  Bucking  Series 
Field — Third   Brush   Control — Cut-Out   Relay 429-409 

JOBS— 150— Wagner  Starting  Motor.  151— Buick  Delco  Motor  Gen- 
erator. 152 — Dodge  Northeast  Motor  Generator.  153 — Dyneto 
System  as  Used  on  the  Franklin  Car.  154 — Gray  and  Davis  Gen- 
erator and  Cut-Out.  155 — Gray  and  Davis  Starting  Motor  Two 
Unit  System.  156 — Hudson  Delco  Motor  Generator  Single  Unit. 
157 — Maxwell  Simms  System.  158 — Remy  Oldsmobile.  159 — 
Wagner  Generator.  160 — Instructions  for  the  Use  of  Weston 
Model  441  Fault  Finder.  161 — When  the  Starting  Motor  Does 
Not  Operate.  162 — Open  Circuit  or  High  Resistance  in  Starting 
Switch.  163 — Open  Circuit  or  High  Resistance  in  Motor  Field. 
164 — Open  Circuit  or  High  Resistance  in  Motor  Armature.  165 — 
High  Resistance  in  Ground  Connection.  166 — High  Resistance 
in  Battery  Terminal.  167 — Short  Circuit  in  Motor.  168 — Short 
Circuited  Wiring  to  Starting  Motor.  169 — Open  Circuit  in  Wir- 
ing to  Motor.  170 — Ground  in  the  Motor  Armature.  171 — Ground 
in  the  Motor  Field.  172 — Grounded  Brush  Holders.  173 — 
Grounded  Wiring  to  Motor.  174 — To  Determine  if  Generator  is 
Generating.  175 — Defective  External  Field  Regulator.  176 — 
Mercury  Tube  Regulator.  177 — Series  Field  Regulator.  178 — 
Vibrating  Regulator.  179 — Third  Brush  Regulation.  180 — Open 
Circuit  in  the  Shunt  Field  of  Generator.  181 — Open  Circuit  in  the 
Armature  of  Generator.  182 — Shunt  Field  of  Generator  is  Short 
Circuited.  183 — Short  Circuit  in  the  Armature  of  Generator.  184 — 
Grounded  Armature  or  Field  or  Brush  Holders  on  Generator. 
185 — Short  Circuit  on  Lines  Between  Generator  and  Battery. 
186 — General  Test  for  Relay  Trouble.  187 — Open  Circuit  in  the 
Voltage  Coil  of  the  Relay.  188 — Open  Circuit  in  the  Series  Coil 
of  the  Relay.  189 — Fitting  Brushes  and  Sanding  Commutator. 
190 — Undercutting  Mica   441-489 

CHAPTER  15 

WIRING  AND  LIGHTING— Single  Wire  or  Grounded  System- 
Double  Wire  or  Insulated  Return — Wiring — Lighting  Switches — 
Head  Lights — Dash  and  Tail  Lamps — Spot  and  Search  Lights — 
Ammeters — Voltmeter — Junction  and  Fuse  Boxes — Bulbs  and 
Sockets — The  Proper  Lamp  for  the  Service — Design  of  Lamps  for 
Use  with  Storage  Batteries— Design  of  Lamps  for  Use  with  Dry 
Cells — Design  of  Lamps  for  Use  with  Battery  Generator  Systems- 
Design  of  Lamps  for  Magneto  Lighting  Systems— Some  Funda- 
mentals of   Light  Projection 490-517 


Table  of  Contents — Concluded 

PAGE 
JOBS — 191 — Splicing  Lighting  Cables.  192 — Sweating  or  Burning  on 
a  Terminal.  193 — Attaching  Wires  to  Lamp  Sockets.  194 — In- 
stalling and  Wiring  an  Ammeter.  195 — Polishing  Lamp  Reflectors. 
196 — None  of  the  Lights  Operate.  197 — Head  Lights  or  Side 
Lights  Not  Operating.  198 — Short  Circuit  in  Branch  of  Lighting 
Circuit.  199 — One  Headlight  or  One  Side  Light  Not  Operating. 
200 — Tail  Light  or  Cowl  Light  Not  Operating.  201 — To  Measure 
the  Current  Taken  by  the  Lights 509-517 

CHAPTER  16 

TIRE  CARE  AND  VULCANIZING— THE  PRINCIPLES  OF 
TIRE  CONSTRUCTION— Tires:  Fabric,  Cord— Tire  Care— 
Trueing  Up  Wheels — Tread  Cuts — Inflation — Fabric  Breaks — Tire 
Repair  Materials:  Tread  Gums — Camel  Back — Cushion  and  Tube 
Repair  Gum — Repair  Fabrics — Cord  Patch — Vulcanizing  Cement — 
Reliners — Valve  Patches — Semi-Cured  Retread  Bands — Soapstone 
— Sectional  Air  Bags — Why  Repairs  Fail — Suggestions  for  Hand- 
ling Repair  Materials — Practical  Vulcanizing  Hints — Vulcaniza- 
tion :     Cures — Tube   Repairs 518-568 

JOBS — 202 — Repairing  Pin  Holes  and  Small  Punctures.  203 — Repair- 
ing Large  Injuries  and  Blow  Outs  in  Tubes.  204 — Splicing  Inner 
Tubes.  205— Vulcanizing  Tube  Splice.  206— Cold  Patching. 
207 — Applying  Valve  Patches  or  Pads.  208 — Replacing  Valve  Stems. 
209 — Outer  Casing  Repairs,  210 — Tearing  Down  Quarter  Section. 
211 — Building  Up  the  Quarter  Section.  212 — Tearing  Down  for 
Half  Section.  213— Building  Up  the  Half  Section.  214— Tearing 
Down  for  Full  Section.  215— Building  Up  the  Full  Section.  216— 
Inside  Section.  217 — Repairing  of  Cord  Tires.  218 — Full  Section 
Cord  Tire.  219— Cord  Tire  Full  Section.  220— Width  of  Breaker. 
221— Repairing  Tread  Cuts.  222— Preserving  the  Tread.  223— Re- 
pairing Scraped  Side  Walls.  224 — Retreading.  225 — Building  Up 
the  Retread.  226— Curing  the  Retread.  227— Third  Circle  Re- 
treading.    228— Retreading    Cord    Tires 538-568 

CHAPTER  17 

GARAGE  SHOP  REPAIR  METHODS— Taps  and  Dies— Forging— 
Soldering — Lead  Burning — Oxy-Acetylene  Welding — Connecting 
and  Starting  Welding  Unit — Properties  of  Metals — Preheating — 
Preparation  of  Welds — Character  of  Flame — Manipulation  of  Blow- 
pipe— Sources  of  Trouble — Steel — Cast  Iron — Malleable  Iron — 
Aluminum — Cutting  of  Steel — Oxy-Acetylene  Cutting 569-614 

JOBS— 229 — Lifting  an  Engine  From  a  Car.  230 — Using  a  Garage 
Press.  231— Using  Taps.  232— Using  Dies.  233— Building  a 
Forge  Fire.  234 — Forging  Hand  Tools.  235 — Hardening  and 
"  Tempering.  236 — Tinning  a  Soldering  Iron.  237 — Soldering  a 
Leaky  Carburetor  Float.  238 — Remove  Carbon  by  Burning.  239 — 
Burning  Connector  Straps  On  Batteries.  240 — Practical  Oxweld- 
ing  Problems.  241 — Adding  Filling  Rod  to  Weld.  242 — Welding 
Heavy  Steel  Plate.  243— To  Fill  Up  a  Section  of  a  Gear  or  Pinion 
that  has  had  a  Tooth  or  Teeth  Stripped.  244— Building  Up  Lugs 
and  Bosses.  245 — Welding  Cast  Iron.  246 — Welding  Automobile 
Cylinders.  247 — Building  Up  of  Teeth  on  Cast  Iron  Gears  or 
Pinions.  248 — Welding  Cast  Aluminum.  249 — Welding  an  Alumi- 
num Crank  Case.  250— Brazing  Malleable  Iron.  251— Brazing  a 
Heavy  Steel  Part  to  a  Light  Steel  Part.  252— Practical  Cutting 
Problems    569-616 

8 


AUTOMOTIVE  TRADE  TRAINING 


CHAPTER  1 
FRAMES  AND  SPRINGS 

Chassis,  as  the  term  is  applied  to  their  product  by  the  manu- 
facturers, has  come  to  mean  all  details  of  the  motor  car,  excepting 
only  the  body.  Standard  manufacturing  practice  is  the  building  of 
one  type  of  chassis,  but  fitting  many  types  of  bodies  onto  it. 

The  line  of  flow  of  power,  or  power  transmission,  should  be 
learned  early  by  the  student,  in  order  that  he  may  understand  the 
value  and  duties  of  the  various  units  of  construction.  When  a  part 
is  mentioned  in  his  hearing  he  should  have  in  mind  instantly  the 
location  of  that  part  or  unit,  or  at  least  its  relative  position  in  general 
design.  He  should  have  in  mind  as  well  its  purpose.  For  instance, 
practically  all  modern  motor  cars  are  equipped  with  gasoline  engines. 
Power  is  transmitted  to  the  crankshaft  and  flywheel  of  the  engine, 
thence  to  the  clutch,  to  the  transmission,  to  the  universals  and  pro- 
pellor  shaft,  to  the  differential,  to  the  rear  axle  shafts,  to  the  wheels, 
and  to  the  road. 

It  must  be  understood  that  these  units  are  always  in  the  line  of 
flow  of  power.  Design  may  vary  in  minor  details  but  that  need 
occasion  no  confusion.  It  is  useless  to  study  about  any  unit  used  in 
the  transmission  of  power  if  its  position  and  interrelation  with  other 
units  are  not  known.  With  these  points  in  mind  any  unit  may  be 
studied  in  detail  and  its  functions  observed. 

Frames. — The  frame  is  so  well  designed  and  constructed  in  most 
cases  that  it  rarely  needs  repairs  more  than  heating  and  straightening 
parts  of  it  thrown  out  of 
position  due  to  wrecks  or 
other  mishaps.  Occasional- 
ly brackets  need  to  be  re- 
placed and  at  times  even  side 
or  cross  members.  In  cases 
of  cracks  in  the  frame,  they 
are  often  welded  without 
removing  either  the  body  or 
the  engine,  or  other  units 
from  the  frame. 

Springs.  —  The   correct 

method  of  springing  a  car  is  ^'^-  ^-    Cadillac  Frame  and  Springs, 

one  over  which  manufacturers  and  designers  have  puzzled  and  labored 
for  years.  On  the  springs  depends  in  large  measure  the  roadability  of 
the  car.  The  springs  dare  not  be  neglected  if  we  would  secure  long 
life  from  them  or  from  the  more  vital  parts  of  the  car.     They  must 


10 


Automotive  Trade  Training 


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Fig.  2.    Plan  View  Studebaker  Chassis  with  Names  of  Parts. 


Frames  and  Springs  11 

take  all  manner  of  twists,  strains,  jars  and  jolts,  besides  carrying 
the  weight  of  the  car  and  load. 

Through  the  front  springs  must  be  transmitted  the  steering 
effort.  That  is,  when  the  wheels  are  turned  there  is  a  tendency  for 
the  car  to  continue  in  its  course  while  the  wheels  and  axle  tend  to 
leave  their  rightful  position  under  the  car.  The  springs  while  relieving 
the  car  of  the  road  shock,  must  also  exert  a  side  strain  or  pressure 
to  carry  the  car  out  of  its  forward  course  to  the  side  and  around  the 
corner.  These  things  it  must  do  and  not  permit  the  steering  gear 
links  to  become  disarranged  so  that  faulty  steering  or  accidents 
result. 

The  front  springs  also  keep  the  front  axle  in  alignment.  If  one 
is  broken,  the  axle  may  drop  back  and  cause  an  accident  or  at  least 
a  hard  steering  car. 


Fig.  1-A.     Cadillac  Motor  Car  Frame. 

To  prevent  breakage  the  following  points  must  be  observed: 

Keep  the  shackles  lubricated  and  snug. 

Keep  the  spring  clips  tight. 

Keep  the  center  bolt  tight. 

Keep  the  leaves  well  graphited. 
What  has  been  said  of  the  front  spring  applies  to  the  rear  spring 
as  well.     Here  we  have  in  many  cases  additional  strains  and  stresses 
due  to  a  greater  load  and  the  fact  that  the  driving  effort  is  transmitted 
from  the  axle  to  the  frame  of  the  car  through  the  springs. 

Radius  Rods. — Radius  rods  are  not  found  on  all  chassis.  They 
may  be  used  on  the  front  or  on  the  rear  to  hold  the  axle  in  line  with 
the  frame  and  the  other  units  of  the  car  while  permitting  the  proper 
spring  action. 

Hotchkiss  Drive. — This  is  the  name  applied  to  the  type  of  spring 
suspension  and  rear  axle  drive  where  the  rear  axle  is  carried  by  semi- 
elliptic  springs.  No  radius  rods,  torque  tubes  or  torque  rods  are 
supplied.  Instead  the  axle  is  clipped  to  the  springs  in  rigid  posi- 
tion, no  turning  at  the  spring  seat  being  permitted.  This  throws 
the  torque  as  well  as  the  driving  effort  and  car  load  all  upon  the 
springs.  In  cases  where  the  rear  axle  Is  supplied  with  a  torque  tube 
or  rod  to  keep  the  axle  from  turning,  under  driving  strains,  the  spring 
seats  are  arranged  with  a  bearing  permitting  a  certain  amount  of 
oscillating  movement. 


12 


Automotive  Trade  Training 


Quarter  Elliptic  Springs. — This  type  of  spring  is  in  use  on  some 
of  the  Hghter  cars  for  both  front  and  rear  axle  work.  The  spring  is 
used  inverted  and  the  heavy  end  is  chpped  rigidly  to  the  frame  of 
the  car.     This  type  is  also  called  the  cantilever. 

Semi-Elliptic. — More  of  this 
type  are  used  than  any  one  other. 
It  is  used  almost  altogether  on 
the  front,  and  in  a  very  large 
number  of  cases  on  the  rear.  Its 
peculiar  advantage  seems  to  be  in 
the  fact  that  it  permits  lively 
spring  action  v^ithin  a  reasonable 
range.  This  results  in  safer  steer- 
ing and  less  rear  axle  trouble. 

Three  -  Quarter  -  Elliptic. — 
Formerly  quite  popular,  this 
spring  has  been  largely  super- 
ceded by  the  semi-elliptic  and 
cantilever  for  rear  end  work. 
Where  used,  the  drive  is  in  most 
cases  through  the  lower  semi- 
elliptic  and  the  added  quarter  is 
attached  to  the  frame  of  the  car 
and  projects  rearward  to  meet  the 
lower  half. 

Full  Elliptic. — Used  in  a  few 
cars  this  spring  is  noted  for  its 
ease  of  riding.  In  the  case  of  the 
Franklin  car  the  drive  as  well  as 
the  steering  effort  is  regulated 
and  controlled  by  or  through  the 
springs.  This  necessitates  very 
careful  and  rigid  mounting  of  the 
upper  half  since  no  radius  rods 
are  used.  In  cases  other  than  the 
Franklin,  radius  rods  are  in  use 
thus  permitting  of  different  types 
of  spring  mountings. 

Cantilever. — For  use  on  the 
rear  end  of  motor  cars  the  can- 
tilever spring  is  favored  by  a 
number  of  manufacturers.  The 
spring  is  shackled  at  the  front 
end,  the  center  is  pivoted,  and  the 


Fig.  3.     Essex  Chassis. 


Frames  and  Springs 


13 


Fig.  4.     Rear  of  Packard  Truck  Chassis,   showing  frame  and  spring  suspension. 
Note   also    Radius    Rod. 


Fig.  5.    Marmon  Springs. 


Fig.  6.     Buick  Hydraulic  Pressed  Steel  Frame. 


14 


Automotive  Trade  Training 


Fig.   6A.    Buick   Cantilever    Spring. 

rear  end  attached  to  the  axle  housing.  The  spring  affords  a  large 
measure  of  riding  comfort,  due  to  its  ability  to  absorb  road  shock 
without  transmitting  the  same  to  the  car  body  and  passengers. 

JOB  1.    TIGHTENING  SPRING  CLIPS. 

Fig.  7  shows  the  proper  method  of  tightening  the  spring  clips.  It  is  not 
advisable  to  draw  up  on  one  of  the  nuts  to  the  neglect  of  the  others,  but  draw 
on  each  in  turn,  so  that  the  same  tension  is  put  on  each.  Owing  to  the  fact 
that  the  clips  and  nuts  and  threaded  portion  of  the  clips  are  exposed  to  all 
manner  of  dirt,  and  are  very  frequently  wet  and  mud  coated,  it  is  to  be  expected 
that  they  will  rust.  They  should  be  tightened  each  month  or  every  2,000  miles. 
Keeping  these  clips  tight  is  the  only  known  spring  insurance.  Proceed  as 
follows  to  tighten: 


Fig.  7.     Tightening   Spring   Clips. 


Frames  and  Springs 


15 


1.  Select  an  end  or  socket  wrench  which  is  a  snug  fit  on  the  clip  nuts. 
Use  a  creeper  to  roll  under  the  car.     Take  an  oil  can  with  you. 

3.  Test  the  nuts  to  see  if  they  are  rusted.  If  they  show  signs  of  sticking 
turn  them  off  rather  than  on.  Use  oil  to  help  loosen  them  and  to  prevent 
further  rust.  When  all  four  nuts  of  any  one  set  of  clips  are  working  freely 
they  should  be  drawn  up  snug  and  tight. 

3.  If  the  car  is  new  there  is  little  likelihood  of  rust,  and  the  clips  may  be 
drawn  tight  at  once. 

4.  Where  a  rusted  clip  nut  is  tightened  before  it  is  freed  on  the  clip  end, 
it  is  very  misleading,  as  the  workman  thinks  he  has  the  job  snug  when  the  clip 
is  still  quite  loose. 

5.  Where  the  small  center  bolt  shows,  this  should  always  be  tested  to  see 
that  the  nut  sets  snug. 

JOB  2.    ADJUSTING  SHACKLE  BOLTS. 

One  of  the  most  annoying  rattles  about  a  car  is  caused  by  the  side  play 
in  the  spring  ends  in  the  shackles. 

In  some  cases  this  can  be  overcome  by  drawing  up  on  the  shackles  and 
in  other  cases  it  is  necessary  to  add  shims. 

TIGHTENING  BY  USE  OF  SHIMS.     FIG.  8. 

1.  First  crowd  the  spring  to  one  side  of  the  shackle  using  a  heavy  screw 
driver  to  pry  with. 

2.  Measure  the  thickness  of  the  shim  required.  This  may  be  sheet  brass 
or  sheet  steel. 

3.  Remove  the  shackle  bolt  and  clean  it  of  all  grease  and  dirt.  Make 
certain  that  the  oil  or  grease  grooves  are  clean. 


SHIMS 


,     SHIMS 


Fig.  8.    Adjusting   Shackle  Bolts  by  the  Use  of  Shims. 

4.  With  a  rag  and  kerosene,  clean  the  eye  in  the  end  of  the  main  spn'ng 
leaf. 

5.  Cut  the  shims  to  the  shape  of  a  washer,  having  drilled  or  punched  the 
hole  first.     If  this  is  not  done  the  shim  is  very  hard  to  hold. 

6.  Put  some  engine  oil  in  the  eye  and  on  the  bolt  and  reassemble  with 
the  shim  in  place.  The  shim  may  be  tight  enough  to  require  some  crowding 
to  get  it  in  place. 

7.  Draw  up  on  the  nut  until  it  is  just  fairly  snug.     Insert  a  cotter  key. 

8.  After  the  car  has  been  in  service  a  short  while  the  shackles  should  be 
inspected  and  tightened  again. 


16 


Automotive  Trade  Training 


TIGHTENING  BY  DRAWING  ON  NUTS.     FIG.  9. 


1.  Proceed  to  remove  and  clean  as  above. 

2.  Replace,  turning  the  bolt  into  the  threaded  shackle  until  no  play  is 
evident.  If  too  tight,  a  very  bad  condition  is  present.  The  shackle  holds  the 
spring  eye  as  in  a  vise  and  the  result  may  be  a  broken  spring  at  a  short  dis- 
tance from  the  spring  eye.  It  is  likely  also  to  give  forth  a  harsh  grating  noise 
as  the  parts  work  together. 

3.  Replace  the  nut  and  cotter  key. 

4.  In  some  cases  the  shackle  side  is 
not  threaded.  In  adjusting  this  type  it 
is  only  necessary  to  draw  up  on  the  nut 
and  replace  the  cotter  key. 

JOB  3.  LUBRICATING  SPRING 
SHACKLES. 
Due  to  the  constant  action  and  the 
weight  carried  as  welUas  the  liability  of 
foreign  matter  to  work  into  them  the 
spring  shackles  are  in  constant  need  of 
attention. 

The  usual  plan  of  lubrication  is  to 
drill  a  hole  through  the  center  of  the 
bolt  and  then  another  one  in  to  meet  this 
midway  between  the  two  ends.  A  flat 
portion  is  also  provided  at  this  point 
to  permit  the  grease  or  oil  to  work 
out  into  the  spring  eye. 

1.  Where  grease  cups  are  used  they  should  have  one  turn  daily  when  the 
car  is  In  service.     Use  a  medium  cup  grease. 

2.  Where  oilers  are  used  they  should  be  kept  full,  or  receive  an  applica- 
tion daily.    . 


Fig.   9.    Adjusting    Shackle    Bolts. 


Saifonet  ^ocHet 


Fig    10.     Aloinito  Method   of  Shackle   Lubrication  on   Ilea   Car. 


Frames  and  Springs 


17 


3.  The  trouble  with  all  shackle  lubrication  is  the  liability  of  the  oil  or 
grease  ducts  stopping  up. 

4.  To  open  up  the  oil  holes  or  ducts  remove  the  bolt  and  clean  as  sug- 
gested in  Job  3. 

5.  Fig.  10  shows  a  special  oiler  and  grease  gun  used  to  lubricate  the  Reo 
car  shackles.  The  bayonet  socket  is  slipped  over  the  bayonet  end  of  the  oiler. 
Grease  may  then  be  forced  from  the  grease  gun  into  the  shackle. 

6.  At  least  once  each  season,  preferably  in  the  spring  after  the  weather 
conditions  are  settled  and  less  mud  will  be  encountered,  the  shackles  should 
be  taken  apart  and  cleaned  thoroughly. 


Fig.  11.     Shackle  Bolts  Worn  for  Lack  of  Lubrication. 


JOB  4.     GRAPHITING  SPRING  LEAVES. 

When  the  leaf  springs  are  assembled  in  the  factory  they  are  properly 
lubricated  by  giving  each  leaf  a  coat  of  oil  or  grease  over  its  entire  surface. 
This  grease  is  worked  out  in  service  and  requires  frequent  replacement. 
Several  preparations  are  on  the  market  which  will  penetrate  through  between 
the  spring  leaves  if  they  are  applied  to  the  side  of  the  spring.  If  the  spring 
is  not  too  dry  a  good  grade  of  oil  will  do  the  same.  The  standard  practice  in 
spring  lubrication  as  followed  in  the  garages  is  as  follows: 

1.  Set  the  jack  under  the  frame  of  the  car  and  remove  the  weight  from 
the  spring. 

2.  Use  some  device  to  spread  the  leaves,  having  first  removed  the  small 
spring  clip  bolt,  if  that  is  possible.  An  old  screw  driver  or  spring  leaf  end  may 
be  driven  between  the  leaves  to  spread  them,  or  a  special  spring  spreader  such 
as  is  shown  in  the  illustration,  Fig.  12,  may  be  used. 

3.     The  best  grease  to  use   for   spring  lubrication  is  powdered   or   flake 
graphite  mixed  with  engine  oil,  or  some  of  the  finer  grades  of  graphite  grease. 

4.  Use  an  old  hack  saw  blade  or  thin  strip  of  sheet  metal  to  insert  the 
lubricant  between  the  leaves. 

5.  Continue  the  work  until  all  parts,  which  it  is  possible  to  separate,  have 


18 


Automotive  Trade  Training 


been  lubricated.     The  grease  will  work  from  these  points  to  those  points  which 
it  was  impossible  to  separate  far  enough  to  insert  the  saw  blade. 
JOB  5.     SPRING  OVER- 
HAUL. 
Where     the     springs     are 
badly  rusted  or  where  there  is 
a  broken  leaf  to  be  replaced  it 
is    necessary    to    remove    the 
spring  from  the  car. 

1.  Jack  up  the  car,  hav- 
ing the  jack  placed  under  the 
frame. 

2.  Block  the  car  frame  in 
this  position. 

3.  Remove  the  shackle 
bolts,  as  well  as  the  axle 
spring  clips, 

4.  Take  the  spring  to  the 
bench  where  the  first  step  is 
to   remove   the   center   bolt.  Fig.  12.    Spreading   Spring  Leaves. 

5.  Remove  the  shorter  leaves,  laying  them  aside.  To  remove  or  separate 
the  longer  leaves,  it  is  necessary  to  open  the  small  spring  clips.  This  is  simple 
in  the  case  of  the  type  shown  in  Fig.  12,  but  where  the  one  piece  type  is  used 
a  chisel  must  be  driven  under  the  end  to  raise  them  sufficiently  to  allow  the 
leaves  to  be  separated. 

6.  Use  a  coarse  grade  of  sandpaper  to  remove  all  rust,  dirt  and  scale. 

7.  Refit  any  new  leaves  needed. 

8.  Apply  an  even  coat  of  graphite  lubricant  to  the  spring  surfaces. 

9.  Reassemble  the  spring,  being  certain  to  have  all  the  long  ends  together. 
Springs  are  very  frequently  made  with  the  bolt  hole  closer  to  one  end  than  the 
other.  In  cases  where  this  is  considerable  it  is  easily  detected,  but  in  slight 
cases  it  is  often  the  source  of  much  trouble. 

10.  When  all  the  leaves  are  laid  together  use  a  "C"  clamp,  or  a  vise  to 
hold  them  until  the  center  bolt  is  in  place. 

11.  Next  see  that  all  clamps  are  properly  tightened:  To  tighten  the  single 
piece  type  a  few  blows  from  a  hammer  are  sufficient. 

12.  Replace  under  the  car  making  certain  that  the  spring  is  not  inserted 
backward.  Where  the  center  bolt  is  offset  the  short  end,  if  a  front  spring,  goes 
to  the  front,  if  a  rear  spring,  the  short  end  goes  to  the  rear  in  most  cases. 
This  is  done  to  give  a  longer  wheel  base. 

13.  All  shackles  should  be  cleaned  and  properly  adjusted. 

JOB  6.     STRAIGHTENING  A  WRECKED  OR  BENT  CAR  FRAME. 

It  very  frequently  happens  that  in  a  wreck  certain  parts  of  the  frame  are 
sprung,  bent,  or  broken.  If  the  trouble  is  merely  a  bent  portion  the  repairman 
may  proceed  with  confidence  to  put  it  back  in  proper  condition. 

1.  Remove  those  portions  of  the  car  mounted  close  to  the  damaged 
part.  This  may  mean  that  only  the  fender  and  skirts  close  to  the  damaged  sec- 
tion need  be  removed,  or  it  may  mean  every  unit  mounted  on  the  frame  must  be 
removed.  If  the  frame  is  sprung  out  of  line  either  vertically  or  horizontally, 
it  will  be  necessary  to  strip  the  frame  to  permit  of  lining  it  with  a  center  wire. 

2.  With  the  damaged  part  exposed  and  accessible,  the  next  step  is  to 
secure  the  proper  equipment  to  handle  the  work.  It  is  far  better  to  use  a 
bending  bar,  or  jacks,  to  exert  the  pressure  than  to  use  a  sledge  to  drive  with. 


Frames  and  Springs  19 

3.  Apply  heat  from  a  welding  flame,  gasoline  torch,  or  kerosene  pre-heat- 
ing  torch  to  the  portion  of  the  frame  which  it  is  desired  to  straighten.  By- 
localizing  the  heat  to  the  damaged  spot  it  is  quite  possible  to  bring  the  portion 
back  to  the  original  position  with  the  least  effort,  and  without  putting  some 
other  part  out  of  line. 

4.  Keep  a  fire  extinguisher  at  hand  in  case  of  need. 

5.  In  case  the  entire  frame  is  out  of  line  it  is  possible  to  chain  the  ends 
to  a  heavy  timber,  set  a  screw  jack  at  the  sprung  portion  and  thus  exert  pres- 
sure at  the  correct  point  to  spring  it  back  into  position. 

5.  When  the  frame  has  been  brought  into  approximate  position,  the 
smaller  bends,  kinks  and  irregularities  may  be  removed  by  heating  and  ham- 
mering.    A  heavy  sledge  to  back  up  the  blows  is  indispensable  for  this  work. 


CHAPTER  2 
STEERING  GEARS  AND  FRONT  AXLES 

The  five  most  common  types  of  steering  gears  are  the  screw  and 
nut,  the  worm  and  sector,  the  worm  and  gear,  the  planetary  gear, 
and  the  pinion  and  sector. 

Any  type  may  be  said  to  be  irreversible  which  has  sufficient  gear 
reduction,  so  arranged  that  there  is  little  or  no  chance  of  the  road 
shock  being  transmitted  to  the  wheel.  That  is,  power  or  effort  can 
be  transmitted  only  from  the  hand  wheel  to  the  road  wheel  and  not 
in  the  reverse  direction.  This  insures  greater  safety  and  comfort 
to  the  driver. 


Fig.  13.     Packard  Twin  Six  Steering  Gear,  Linkage  and  Front  Axle. 

Planetary  Steering  Gear. — The  planetary  type,  as  arranged  on  the 
Ford  steering  gear,  is  shown  in  Fig.  29.  The  brass  internal  gear  is 
held  rigid  by  the  steering  gear  post.  The  pinion  gear  on  the  steel 
shaft  attached  to  the  hand  wheel  is  rotated  with  it.  The  planetary 
gears  are  thus  given  two  motions.  First  they  are  caused  to  rotate 
on  their  central  pivots,  but  they  cannot  rotate  on  their  pivots  without 
causing  the  spider  on  which  they  are  mounted  to  rotate.  While 
rotating  each  planetary  gear  moves  forward  or  backward  in  a  circle 
around  the  central  gear  within  the  outer  gear.  From  the  spider  shaft 
the  steering  effort  is  transmitted  to  the  steering  arm  and  then  through 
the  drag  link  to  the  steering  knuckles  and  wheels.  This  is  somewhat 
the  same  principle  as  used  in  the  Ford  transmission  for  gear  reduc- 
tion.    The  gear  reduction  is  approximately  4  to  1. 

20 


Steering  Gears  and  Front  Axles 


31 


Inject  /a  trie  ant  for  t>ear/n(^^ 
I^emoi^e  p/uq  to  repfen/st?--.^^^ 
ca^e  tvith  lutncant 
Pinion  and  <^ear  adju^stment 
.^Steennc^  spindle 
Gear  nousincf 


Front  i^heel 
t?eann<^'S 


hteerwf  arm 
<5teerin<^  connectinc^  rod 
'-^teerin^f  react7  rod 
^/3dju<stai>/e  tfoke  on  ncftif  hand  end 


Throttle  fetter 
ySparM  Jeirer 


Fig.    14.     Reo    Steering   Gear  and   Linkage. 


Fig.  15.    Dodge  Steering  Gear. 


22 


Automotive  Trade  Training 


Worm  and  Gear. — The  worm  and  gear  secures  its  name  from 
its  type  of  construction.  A  worm  is  fastened  onto  the  lower  end  of 
the  shaft  having  the  hand  wheel  attached  to  the  upper  end.  Turning 
the  worm  causes  the  gear  shaft  in  mesh  with  it  to  be  rotated  or 


^^*w^J^B  ■Hi^'^^^ 

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\                                       *  1 

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I 

ft 
( 

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,jo 

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Fig.  16.    Gemmer  Worm   and   Gear   Steering  Gear. 

oscillated.  This  gear  shaft  in  turn  carries  the  steering  gear  arm.  An 
attempt  to  turn  the  worm  and  hand  wheel  by  turning  the  steering 
gear  arm  will  show  exactly  how  irreversible  the  transmission  of 
power  may  be.  Turning  the  hand  wheel  gives  an  idea  of  the  power 
developed. 


Steering  Gears  and  Front  Axles 


23 


Fig.  17.     Lavine  Screw  and  Nut  Gear,  Details  and  Assembly. 

The  gear  ratio  varies  from  about  7  to  1  in  touring-  cars  to  about 
11  to  1  in  the  case  of  heavier  cars  and  trucks,  according  to  the  duty 
imposed  on  it. 

Worm  and  Sector. — This  is  approximately  the  same  as  the  worm 
and  gear  with  the  exception  that  since  only  a  sector  of  gear  is  used 
it  cannot  be  adjusted  for  wear  as  can  the  worm  and  full  gear,  where 
a  new  quarter  may  be  turned  to  come  in  contact  with  the  worm, 
thus  compensating  for  the  gear  teeth  which  may  have  been  worn 
thin. 

The  Screw  and  Nut. — The  screw  and  nut  type  is  compact  and 
efficient.     Instead  of  the  worm  a  screw  thread  is  used.     The  thr 


24 


Automotive  Trade  Training 


on  the  screw  is  cut  both  right  and  left  hand.  One  side,  or  half  of 
the  head  or  nut,  is  cut  with  left-hand  threads,  and  the  other  side  of 
the  nut  or  head  is  cut  with  right-hand  threads  as  shown  in  Fig.  17. 
Consequently,  as  one-half  of  the  nut  is  going  up  on  the  thread,  the 
other  side  is  going  down,  and  vice  versa.  The  half  nuts  or  heads  are 
so  arranged  as  to  actuate  rollers  or  trunnion  blocks,  which  in  turn 
actuate  the  shaft  and  steering  gear  arm.  This  type  is  termed  the 
semi-irreversible  as  it  will  permit  the  front  wheels  to  follow  the  sand 
or  mud  ruts  without  any  care  from  the  driver.     On  the  other  hand 


Fig.   18.     Ross   Fore   aud   Aft    Steering   Gear   for   Trucks. 


Steering  Gears  and  Front  Axles 


25 


not  enough  road  shock  is  transmitted  to  the  wheel  to  cause  undue 
tiring  of  the  driver. 

Pinion  and  Sector. — Here  the  worm  and  screw  thread  is  replaced 
by  a  pinion.  The  pinion  actuates  a  section  of  gear  similar  to  a  ring 
or  bevel  gear.  The  pinion  and  sector  are  exposed,  not  being  encased 
in  the  housing  as  in  all  other  types.  The  action  is  very  direct  and 
road  shock  is  transmitted  rather  forcefully  to  the  hand  wheel.  This 
type  is  obsolete. 

FRONT  AXLES 

Front  Axle  Types. — The  types  of  front  axles  most  popular  today 
are  the  Elliot,  Reversed  Elliot,  and  Lemoin.     In  a  few  cases  tubular 


Fig.  19.     Ross  Cross   Steering  Gear  for   Trucks. 


26 


Automotive  Trade  Training 


axles  are  still  used  though  this  is  comparatively  seldom.  The  usual 
type  or  style  of  section  of  the  axle  resembles  the  "I"  beam.  Light- 
ness and  strength,  together  with  great  ability  to  resist  crystalliza- 
tion and  consequent  cracking  and  breaking,  are  prime  essentials.     A 


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good  piece  of  axle  steel  will  stand  considerable  bending  and  straight- 
ening while  cold  without  breaking. 

Axle  Repair  Work. — The  usual  types  of  repair  jobs  on  the  front 


Steering  Gears  and  Front  Axles 


27 


axle  include,  rebushing  of  yokes,  replacing  of  "King  Bolts"  or  steering 
knuckle  pivots,  aligning  front  wheels,  adjusting  front  wheel  bearings, 
straightening  sprung  axles,  replacing  or  straightening  front  radius 
rods,  and  work  of  like  nature. 

Front  Axle  Design. — In  the  case  of  the  front  axle  as  elsewhere 
the  student  must  understand  the  principles  incorporated  in  the  design 


Fig.  22.     Axle  End  showing  Spindle  and  Steering  Arm. 

of  the  axle  if  he  is  to  make  repairs  on  it,  otherwise  he  may  do  that 
which  would  leave  the  car  unsafe  to  be  operated  on  the  highways 
in  some  cases,  and  in  other  cases  be  the  source  of  continuous  expense 
to  the  owner.  In  designing  the  front  axle  three  important  items  are 
cared  for.  These  are  camber,  toe-in,  and  castering  effect.  The  repair- 
man must  be  able  to  retain  these  in  making  repairs  in  the  same 
proportion  in  which  they  were  originally  provided. 


Oi>)n  Dollar  ittmi   Storint  Ki«U<- 


Fig.  23.     Overland  Four  Front  Axle.     Note  Camber  provided. 


28 


Automotive  Trade  Training 


Camber. — The  camber  of  the  front  axle  is  provided  for  several 
reasons.  First  to  allow  the  car  to  hold  the  road  better,  especially 
when  the  road  is  crowned.  A  second  reason  is  to  have  the  weight  of 
the  car  and  load  transmitted  in  a  direct  line  through  the  center  of 
the  spokes  of  the  front  wheel,  (which  is  usually  dished)  from  the  hub 
to  the  rim,  to  the  tire,  to  the  road.  If  no  camber  were  provided  the 
wheel  would  tend  to  exercise  an  undue  strain  on  the  steering  knuckle 
and  spindle.  A  third  reason  is  that  the  closer  under  the  steering 
knuckle  pivot  the  center  of  the  tire  is  brought  as  it  comes  in  contact 
with  the  road,  the  less  the  effort  required  to  steer  the  car.  A 
correspondingly  less  degree  of  road  shock  is  transmitted  to  the  steer- 
ing wheel.  The  amount  of  camber  varies  from  a  slight  amount  to 
as  much  as  three  inches.  That  is,  the  center  of  the  tires  at  the  top 
of  the  wheels  will  stand  as  much  as  three  inches  farther  apart  than 
the  center  of  the  tires  at  the  bottom  of  the  front  wheels.  The  method 
of  providing  the  camber  is  indicated  in  Fig.  23. 

Toe-in. — Toe-in,  as  it  is  called,  is  provided  by  bringing  the  front 
of  the  front  wheels  closer  together  than  the  rear  of  them.  This  is 
done  to  make  the  car  easier  to  steer,  and  to  compensate  for  the 
tendency  of  the  wheels  to  flare  out  at  the  front  when  being  operated 
at  speed  over  the  road.  The  amount  of  the  toe-in  provided  falls 
within  rather  definite  limits,  3/16"  to  5/16"  being  the  standard  amount 
allowed.     Refer  to  Fig.  24. 


0 


riEWEDTFiOM   TOP 


--— — crx 


C 


'/3* SHOULD  3E  1/4'GaEaTER  TIfaifX 


Fig.  24.     Illustrating  Toe-in. 


Steering  Gears  and  Front  Axles 


29 


Castering  Effect. — This  also  is  provided  that  steering  may  be 
easier  and  safer.  Instead  of  allowing  the  steering  knuckle  pivot  to 
stand  straight  up  and  down,  or  perpendicular,  the  lower  end  is 
brought  forward  and  the  upper  end  is  thrown 
backward.  This  is  much  the  same  as  the  pivot 
is  arranged  in  a  bicycle.  Fig.  25  shows  how 
the  steering  axis  is  thus  brought  ahead  of  the 
point  of  actual  contact  with  the  ground.  This 
construction  is  the  feature  that  permits  the 
rider  of  the  bicycle  to  ride  and  steer  the  wheel 
without  touching  the  handle  bars.  The  same 
principle  is  in  use  in  the  casters  on  which  a 
piece  of  furniture  rolls  over  the  floor.  The 
casters  always  align  themselves  with  the  direc- 
tion in  which  the  piece  is  being  moved.  The 
castering  feature  as  applied  to  automobiles  will  cause  the  front  wheels 
to  align  themselves  with  the  direction  of  travel  of  the  car.  After 
rounding  a  curve,  the  wheels  automatically  attempt  to  straighten  out 
and  keep  straight  with  the  car  and  road. 

Steering  Knuckle  Arm  Design. — Still  another  feature  of  front 
axle  design  is  the  shape  and  position  of  the  steering  knuckle  arms. 
Generally  speaking,  if  lines  were  drawn  through  the  centers  of  steer- 
ing knuckle  pivots  and  tie  rod  bolts  they  would  meet  close  to  the 
center  of  the  rear  axle.  This  may  be  noted  in  Fig.  2.  This  provides 
the  proper  mechanical  movement  and  length  of  the  lever  arm  to 
cause  the  front  wheels  to  be  held  in  a  perpendicular  position  with 


Fig.  25.  The  steering 
axis  meets  the  ground  in 
advance  of  the  point  of 
contact    of    the    wheel. 


Fig.  26.    Application  of  Timlien   Roller  Bearings  to  the  Spindle  and  to  the 

Knuckle  Head. 

reference  to  whatever  radius  they  may  be  traveling  on  in  rounding 
a  corner. 

Since  the  front  axle  of  the  car  is  fixed,  the  front  wheel  on  the  side 
toward  which  the  turn  is  made  will  always  be  ahead  of  the  other  one 
with  reference  to  the  center  of  the  curve  being  rounded.  As  a  con- 
sequence of  this  the  same  radius  would  not  strike  the  center  of  each 


30  Automotive  Trade  Training 

wheel,  and  since  the  wheels  must  be  maintained  perpendicular  to  the 
radius  the  car  is  traveling  on  the  wheels,  they  would  not  be  parallel 
on  a  curve  as  they  would  be  on  a  straightaway.  A  test  made  on  cars 
in  the  shop  will  prove  this.  In  attempting  to  verify  the  above,  first 
turn  the  wheels  of  the  car  to  the  side  sharply.  If  lines  are  next 
stretched  along  the  sides  of  the  front  wheels  it  will  be  found  that 
they  will  meet  at  a  distance  ahead  of  the  car  depending  on  the 
amount  the  wheels  are  turned  aside  and  on  the  length  of  the  wheel- 
base  of  the  car. 

These  matters  are  not  presented  with  the  idea  of  confusing  the 
student,  but  rather  that  he  may  have  such  an  understanding  of  the 
principles  of  design  that  an  axle  to  be  repaired  in  any  detail  may  be 
so  cared  for  as  to  insure  safety  and  service  without  undue  wear  and 
strain  being  placed  on  tires,  knuckles,  spindles,  bearings,  bushings, 
steering  gears,  and  other  details  affected. 

JOB  7.    TESTING  AND  RE-ALIGNING  FRONT  WHEELS. 

Service  and  safety  are  absolutely  dependent  on  proper  alignment  of  the 
front  wheels. 

1.  Jack  up  both  front  wheels. 

2.  Turn  them,  noting  whether  they  run  true. 

3.  Resting  a  soft  pencil  on  a  block  or  box  mark  the  center  of  each  tire  as 
the  wheel  turns. 

4.  Set  the  wheels  in  true  with  the  car.     (Straight  ahead.) 

5.  Measure  from  center  to  center,  or  from  mark  to  mark  on  the  exact 
front  of  the  wheels.  Use  a  strip  of  wood,  marking  the  distance  with  a  pencil. 
A  better  device  is  the  adjustable  measuring  device  illustrated  in  Fig.  27.  This 
insures  the  same  distance  from  the  floor  being  used  at  the  front  and  rear  of  the 
wheel. 

6.  Test  the  marks  on  the  rear  of  the  tires.  Is  there  any  difference  in  the 
measurement? 

7.  How  much  difference  should  there  be,  and  why  is  this  allowed? 

8.  What  is  camber?     How  much  is  allowed? 

9.  What  is  toe-in?     How  much  should  be  allowed? 

10.  If  the  amount  of  toe-in  is  not  correct,  the  clamping  screw  in  the  ad- 
justable tie  rod  yoke  should  be  loosened.  Remove  the  yoke  pin  and  turn  the 
yoke  on  or  off  as  desired. 

11.  After  the  adjustment  is  again  tested  and  found  to  be  correct,  the  yoke 
pin  and  the  locking  or  clamping  screw  are  replaced  and  tightened.  Make 
certain  that  the  cotter  keys  are  in  place. 

JOB  8.  OVERHAUL  FORD  FRONT  RADIUS  ROD. 

A  common  fault  of  the  Ford  car  is  to  have  the  front  radius  rod  sprung  by 
striking  a  rut  or  curb. 

1.  Remove  the  lower  half  of  the  ball  joint  bearing  which  is  the  ball  joint 
cap.     Place  parts  where  they  will  be  kept  safely. 

2.  Remove  cotter  keys  from  front  ends  of  radius  rods. 

3.  Loosen  nuts  until  just  even  with  ends  of  radius  rod. 

4.  With  a  lead  or  bronze  mallet  jar  the  ends  loose  from  the  axle.  If  no 
soft  metal  hammer  is  at  hand  use  a  wood  mallet,  or  a  piece  of  hard  wood  under 
a  hammer. 


Steering  Gears  and  Front  Axles 


81 


»-iIv 


Fig.  27.     Testing  the  Alignment  of  Front  Wheels. 
Remove  nuts.     Place  away. 


Remove  radius  rod  and  clean. 

Test  rod  for  alignment  and  any  bends. 

If  out  of  true,  get  instruction  for  straightening  on  arbor  press. 

9.  In  straightening  Ford  parts  of  this  nature  no  heat  is  applied,  they  are 
straightened  cold. 

10.  Have  work  inspected  and  if  approved  reassemble  in  the  car.     Do  not 
reverse  in  axle  or  it  will  throw  the  front  axle  out  of  plumb. 

11.  Inspect  to  see  if  all  is  tight  and  all  cotters  in. 


32  Automotive  Trade  Training 

JOB  9.     OVERHAUL  FORD  FRONT  WHEELS  AND  BEARINGS. 

1.  Jack  up  car. 

2.  Remove  hubs. 

3.  Remove  cotter  keys. 

4.  Remove  castellated  nut  and  washer. 

6.  Remove  adjustable  bearing  cone.  One  spindle  has  right  and  other 
left-hand  threads.     Why? 

6.  Remove  wheel. 

7.  Remove  felt  washers. 

8.  Clean  all  parts. 

9.  To  remove  and  inspect  balls  first  compress  and  remove  ball  retainer. 

10.  Inspect  all  steel  balls  for  cracks  and  pits.  Remove  defective  ones  and 
replace  with  good.     If  very  bad,  all  should  be  replaced. 

11.  The  inner  bearing  cups  may  be  pressed  or  drifted  out  if  their  removal 
is  found  necessary.     They  are  a  press  fit  and  should  be  replaced  when  worn. 

12.  All  parts  being  cleaned  they  may  be  reassembled.  Pack  with  cup 
grease. 

13.  After  wheel  is  in  place,  test  for  side  play  due  to  too  loose  an  adjust- 
ment. Test  for  tightness  as  too  tight  will  cause  undue  wear.  One  good  way 
to  get  proper  adjustment  is  to  tighten  until  the  wheel  shows  signs  of  binding, 
then  back  off  the  adjustable  cone  until  the  wheel  runs  freely. 

14.  Put  on  washer  and  nut,  and  have  inspected. 

15'.     If  approved,  place  in  cotter  key;  a  new  key.     Why?   ^ 

JOB  10.    TIGHTENING  UP  FORD  STEERING  GEAR. 

Should  the  steering  gear  become  loose,  that  is,  so  that  a  slight  movement 
of  the  wheel  does  not  produce  immediate  results  it  may  be  tightened  in  the 
following  manner: 

1.  Disconnect  the  two  halves  of  the  ball  sockets  which  surround  the  ball 
arm  at  the  lower  end  of  the  steering  post  and  file  off  the  surface  until  they  fit 
snugly  around  the  ball. 

2.  If  the  ball  is  badly  worn  it  is  best  to  replace  it  with  a  new  one.  Also 
tighten  the  ball  caps  at  the  other  end  of  the  steering  gear  connecting  rod  in  the 
same  manner. 

3.  If  the  bolts  in  the  steering  spindle  arms  appear  to  be  loose,  the  brass 
bushings  should  be  replaced  with  new  ones.     Refer  to  Fig.  28. 

4.  Excessive  play  in  the  front  axle  parts  may  be  detected  by  grasping  one 
of  the  front  wheels  by  the  spokes  and  working  it  in  such  manner  as  to  show  up 
any  excessive  wear. 

5.  After  the  car  has  been  in  service  two  or  three  years  excessive  play  in 
the  steering  gear  may  make  necessary  the  renewal  of  the  little  pinions,  as  well 
as  the  brass  internal  gear  just  underneath  the  steering  wheel  spider. 

6.  It  is  also  advisable  to  inspect  the  front  hangers  occasionally  to  over- 
come any  excess  vibration.  If  found,  remove  old  hangers  and  replace  with 
new  ones. 

JOB  11.    OVERHAULING  AND  REBUSHING  FORD  FRONT  AXLE. 

Refer  to  Fig.  28. 

1.  Remove  wheels. 

2.  Remove  radius  rod. 

3.  Remove  steering  knuckle   spindles  by  removing  nut  and   spindle   or 
king  bolt. 

4.  Press  out  spindle  body  bushing. 


Steering  Gears  and  Front  Axles 


33 


5.  Press  in  new  ones. 

6.  Press  out  spindle  connecting  rod  bushing. 

7.  Press  in  new  ones. 

8.  Reassemble,  using  care  to  see  that  all  parts  fit  properly.     In  this  work 
it  may  be  necessary  to  ream  the  bushings  to  fit  them  to  the  bolts.     Any  burrs 


Spindle  Oiler 
Spindle  Bolt 
Spindle  Body  Bushing 
Spindle  Con  Rod  Boll 
Spindle  Con  Rod  Yok^ 
Spindle  Arm 


Clamp  Boll 
Spindle  Arm  Nut 
Spindle  Body  Bushing 
Spindle  Bolt  Nut 


Spoke 

Felt  Washer 

Hub  Bolt 

Large  Ball  Race 

Hub  Flange 

Hub 

Spindle 

rease  Chamber! 
Ball  Bearings 

djusting  Cone. 

ock  Nut 

ub  Cap 
Washer 
Ball  Retainer 
Small  Ball  Racei 


Stationary  Cone 
Ball  Retainer 
ust  Ring 


Fig.  28.     Ford  Front  Axle  Details. 

may  be  removed  from  bushings  with  a  scraper,  knife  or  fine  file. 
9.     Put  on  wheels. 

10.  Test  wheels  for  alignment, 

11.  Test  job  for  any  unfinished  work. 


Pig.  29.     Ford   Steering  Gear. 


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MQKw  Hie  mft  «ii  %t^  •!  tilt 


xmo  xmfiimeoiiT  wasBL 


Steering  Gears  and  Front  Axles 


35 


JOB  14.     REPLACING  FRONT  WHEEL  SPINDLE  CONES  OR  RACES. 

It  sometimes  is  necessary  to  remove  the  cone  or  bearing  race  which  fits 
over  the  spindle.  This  is  shown  in  Fig.  30.  These  races  are  worn  in  normal 
service  but  at  times  a  cracked  ball  or  bearing  will  hasten  the  wear.  When 
worn  or  pitted  they  must  be  removed  and  new  ones  installed. 

1.  Remove  the  wheel. 

2.  With  a  hammer  and  drift,  work  the  stationary  cone  or  bearing  race 
off,  by  driving  on  the  back  of  it. 

3.  When  replacing  use  a  piece  of  pipe  for  a  drift  as  shown  in  Fig.  31. 

4.  Do  not  permit  the  pipe  to  rest  on  the  shell  which  is  the  roller  retainer, 

or  it  will  be  broken.  In  the 
case  of  the  inner  stationary 
cone  as  used  on  the  Ford  and 
other  ball-bearing  types,  the 
same  device  is  useful  as  it 
insures  an  even  pressure  and 
a  workmanlike  job. 

5.  Considerable  force  is 
at  times  necessary  to  drive  a 
cone  or  race  off  or  on.  One 
a  bit  undersize  will  force 
some  of  the  softer  metal  of 
the  spindle  off  as  it  is  forced 
on,  thus  cutting  it  down  to  a 
slightly  smaller  size. 

6.  The  workman  must 
remember  that  the  cones  and  races  are  hardened,  and  striking  them  with  a 
hardened  hammer  will  very  likely  chip  them  and  result  in  future  damage. 

JOB  15.     REPLACING  WHEEL  BEARING  CUPS. 

The  hardened  steel  races  mounted  in  the  front  wheels  for  the  ball  bearings 
are  called  outer  and  inner  ball  cups.  These  are  press  fits.  To  renew  proceed 
as  follows: 

1.  Remove  the  wheel  and  clean  it  of  all  grease.  A  stream  of  hot  water  is 
beneficial  in  this  work,  or  kerosene  and  a  stiff  paint  brush  may  be  used. 

2.  Insert  a  block  of  wood  or  a  pipe  through  the  rear  of  the  hub  as  the 
wheel  lies  on  a  block  on  the  bench. 

3.  Making  certain  that  the  drift,  which  is  the  pipe  or  the  stick  of  hard 
wood,  rests  on  the  ball  cup  in  the  outer  end  of  the  wheel  hub,  it  may  be  driven 
downward.     This  will  force  the  cup  out. 

4.  Having  the  outer  ball  cup  out,  there  is  more  room  available  to  drive 
the  inner  cup  outward  having  the  drift  inserted  from  the  outer  hub  end. 

5.  When  the  new  cups  are  being  inserted  care  must  be  used  not  to  strike 
them  with  a  steel  hammer.  Use  a  lead  mallet,  or  a  block  of  wood  may  be  used 
as  a  drift. 

6.  Repack  with  grease  and  reassemble  the  wheel.  Discard  any  broken, 
chipped,  or  undersize  balls. 


Fig.  31.     Mounting  Wheel   Bearing. 


JOB  16.     STRAIGHTENING  DAMAGED  FRONT  AXLES. 

It  is  quite  possible  to  straighten  front  axles  and  use  them  with  safety  and 
assurance  of  proper  service  if  the  mechanic  has  proper  facilities  for  doing  the 
work  and  making  the  proper  tests  when  the  work  is  in  progress.  For  those 
desiring  to  attempt  work  of  this  nature  the  following  suggestions  are  given: 


36  Automotive  Trade  Training 

1.  Remove  the  axle  from  the  car,  blocking  the  car  so  that  there  is  no 
danger  of  it  falling  on  the  workmen. 

2.  From  such  portion  of  the  axle  as  appears  to  be  left  in  its  original  shape, 
make  an  estimate  of  the  work  needed  to  bring  the  sprung  portions  back  to 
shape. 

3.  If  it  is  a  Ford  axle  or  only  sprung  a  slight  amount,  it  is  not  advisable  to 
heat  it,  instead  straighten  it  while  cold.  This  means,  it  must  be  placed  in  the 
garage  press  in  such  manner  that  the  correct  force  may  be  brought  to  bear. 

4.  If  the  axle  is  one  of  the  heavier  type  and  rather  badly  damaged  it  may 
be  heated  at  the  point  showing  most  damage.  When  heated  to  a  red  heat  it 
may  be  caught  in  a  heavy  vise  and  straightened  by  means  of  pulling  on  the  pro- 
jecting end.     A  bending  bar  is  of  assistance  in  this  case. 

5.  Avoid  the  use  of  a  hammer  as  far  as  possible  as  the  appearance  as  well 
as  the  actual  value  of  the  job  is  marred  by  any  appreciable  amount  of  hammer- 
ing.    In  some  cases  the  use  of  the  hammer  is  necessary. 

6.  When  the  axle  appears  to  be  in  proper  shape,  test  by  setting  two  fram- 
ing squares  on  the  spring  perches  and  sighting  over  the  blades  to  see  if  they 
are  in  alignment.     If  so,  the  central  part  of  the  axle  has  no  twists. 

7.  Insert  a  piece  of  cold  rolled  steel  in  each  of  the  yokes.  Sight  them  to 
see  if  they  are  parallel.  If  only  one  end  of  the  axle  was  damaged,  this  end 
should  be  brought  to  the  undamaged  one  by  applying  heat  between  the  spring 
seat  and  yoke,  and  after  gripping  the  axle  in  the  vise  again,  use  a  bending  bar 
to  twist  it  into  alignment  with  the  good  end. 

8.  I'f  both  ends  are  thought  to  be  out,  castering  must  be  provided  to  a 
slight  extent.  To  test  for  this,  sight  a  cold  rolled  steel  bar  fitted  into  the  yoke 
with  a  square  blade  set  on  the  spring  seat.  If  they  align  there  is  no  caster.  If 
the  top  end  of  the  cold  rolled  bar  or  pin  shows  at  an  angle  with  the  square,  the 
top  is  back  of  the  blade  and  the  bottom  would  be  ahead  of  the  blade,  the  axle 
has  caster.  A  slight  amount  is  all  that  is  needed.  If  the  reverse  of  the  above 
is  true  the  fault  must  be  remedied  or  steering  will  be  made  difficult  and  actually 
unsafe. 

9.  In  straightening  and  in  replacing  the  axle  the  repairman  must  keep  in 
mind  at  all  times  which  is  the  front  and  which  is  the  rear  of  the  axle. 

10.  Unless  especially  equipped  for  such  work  no  attempt  should  be  made 
to  heat,  treat  or  temper  the  axle.  Allow  it  to  cool  and  it  will  be  in  condition  to 
put  into  service.     Do  not  cool  in  water. 

JOB  17.     REPLACING  STEERING  KNUCKLE  BODY. 

When,  because  of  natural  wear  or  accident,  it  is  necessary  to  replace  the 
steering  knuckle  spindle  body,  proceed  as  follows: 

1.  Jack  up  car,  remove  wheel  and  put  aside. 

2.  Remove  pivot  bolt  sometimes  called  "king  pin"  or  "bolt." 

3.  This  permits  the  spindle  body  to  be  lifted  out  of  the  axle  yoke. 

4.  Remove  bearing  or  stationary  cone. 

5.  Fit  pivot  bolt  into  the  new  spindle  body  bushings. 

6.  Replace  and  reassemble  wheel  in  position. 

JOB  18.     STEERING  GEAR  LUBRICATION. 

One  of  the  most  important  points  to  keep  well  lubricated  is  the  steering 
gear  mechanism.  The  bearing  just  under  the  steering  wheel  is  lubricated  with 
engine  oil.  The  working  parts  in  the  gear  case  are  lubricated  usually  by  a 
heavy  oil,  or  a  light  grease,  or  a  mixture  of  engine  oil  and  cup  grease.     The 


Steering  Gears  and  Front  Axles 


37 


type  of  lubricant  is  dependent  to  a  certain  extent  on  the  nature  of  the  construc- 
tion. 

1.     Oil  the  top  bearing.     (Fig.  32.) 


Ott  PlUC 


Fig.   32.     Steering   Gear  Adjustment   and   Lubrication.    U.   S.  Model. 


2.  Oil  controls  (spark  and  throttle))  several  drops  to  each  point  ol 
bearing  or  wear. 

3.  Inspect  gear  for  any  other  points  requiring  oil  lubrication. 

4.  Fill  the  case  with  grease,  or  heavy  oil,  using  the  kind  specified  by  the 
manufacturer. 

5.  Locate  and  fill  any  grease  cups. 

6.  To  lubricate  the  drag  link  it  is  necessary  to  remove  the  boot  covering 
the  ends.  (Used  in  most  cases.)  Remove  all  dirt  and  hard  grease.  If  in  bad 
condition,  it  is  well  to  take  apart  and  clean  before  repacking.  Finally  replace 
boot  after  packing  all  parts  in  cup  grease  to  insure  lubrication,  and  exclude 
mud  and  dirt. 


38 


Automotive  Trade  Training 


JOB  19.     ADJUSTING  STEERING  GEARS. 

Since  the  safety  of  the  car  and  the  occupants  is  dependent  on  the  proper 
adjustment  of  the  steering  gear  and  its  proper  functioning,  too  much  care 
cannot  be  given  to  it.  The  worm  and  gear  type  is  provided  v^ith  several 
adjustments,  in  most  cases.  The  most  common  adjustment  is  to  remove  the 
up  and  down  or  endwise  play  of  the  worm  within  the  housing. 

1.  Inspect  the  gear  case  for  the  locking  screw  nut  or  bolt. 

2.  Release  the  locking  device. 

3.  With  a  large  wrench  turn  the  adjusting  nut  down  on  the  thrust  bearing 
until  all  the  end  play  is  taken  out.     Note  Figs.  33  and  34,     If  no  other  play  is 


Fig.  33.     Allen   Steering  Gear  Adjustment. 

evident   it   may   be   necessary   to   release   the   adjusting   nut   a  bit   to   allow   the 
required  play  in  the  steering  wheel.     This  should  be  from  %"  to  1^". 

4.  Some  gears,  as  for  instance  the  Dodge  and  Allen,  are  provided  with 
eccentric  bushings  for  the  gear  shaft  to  work  in.  By  turning  these  bushings 
which  are  originally  assembled  with  the  thin  side  next  to  the  worm,  the  play 
between  the  worm  and  the  gear  may  be  removed  and  the  wear  compensated 
for.     This  adjustment  is  shown  in  Fig.  33. 

5.  Another  adjustment  is  shown  in  the  same  figure.  This  is  the  thrust 
washer  and  screw  arrangement  holding  the  gear  in  position.  Sometimes  when 
this  is  not  provided  in  this  way  it  is  necessary  to  remove  the  case  cover  and 
remove  a  thin  shim  thus  taking  the  play  out  at  that  point.  To  prevent  undue 
wear,  none  of  the  adjustments  mentioned  should  be  made  too  tight. 


JOB  20.     OVERHAULING  DRAG  LINK. 

In  the  ends  of  the  drag  link  are  mounted  several  cups,  a  spring,  and  an 
adjusting  screw  locked  by  a  long  cotter  key.  This  is  the  standard  type  of  drag 
link  construction.     To  clean  and  adjust  proceed  as  follows: 

1.  Fig.  13  shows  the  steering  connecting  rod  or  drag  link.  Remove  the 
cotter  key  from  the  end. 


Steering  Gears  and  Front  Axles 


39 


2.  With  a  heavy  screw  driver  remove  the  adjusting  nut  through  the  slot 
of  which  the  cotter  key  is  ordinarily  placed. 

3.  Remove  the  hardened  ball  cups  and  the  compression  spring,  and  pull 
the  drag  link  from  the  steering  arm  ball. 

4.  Clean  all  parts,  inspecting  same  for  wear. 

5.  Replace  parts  in  proper  order  having  first  packed  them  in  medium  cup 
grease. 

6.  Do  not  draw  the  adjustment  too  tight  or  undue  wear  will  result.  If 
too  loose,  the  steering  gear  is  not  safe  and  is  likely  to  be  noisy. 

7.  Each  end  is  similarly  constructed  although  not  exactly  alike  in  every 
case.  When  removing  parts,  note  very  carefully  their  proper  relation  to  each 
other.  Replace  in  their  former  order.  As  a  rule  the  new  adjustment  will  be  a 
bit  closer  than  the  old  to  account  for  the  wear. 

8.  Inspect  and  make  very  certain  that  both  cotter  keys  are  in  position. 


Fig.  34.    Thrust  Bearing  Worm  Adjustment. 


CHAPTER  3 
REAR  AXLES  AND  BRAKES 

Rear  axles  may  be  divided  into  two  general  classes,  live  axles 
and  dead  axles.  The  live  axle  is  used  universally  in  passenger 
vehicles.     The  dead  axle  is  still  used  to  some  extent  in  trucks. 

Live  Axles. — As  to  the  relative  merits  of  live  axles  of  various 
types,  designers  have  contended  for  some  years.  Each  has  its 
peculiar  advantages  as  well  as  disadvantages.  These  will  be  men- 
tioned as  the  types  are  considered.  In  considering  any  axle  to  deter- 
mine what  type  it  is,  one  main  point  only  need  be  remembered  and 
that  is  whether  or  not  the  axle  shaft  actually  carries  any  load  or 
strain  other  than  that  of  transmitting  the  turning  or  driving  effort  to 


Pig.  35.    Dead  Axle  Load  Carrying  Member  as  used  on  Torbensen 
Internal   Gear   Rear  Axles. 

the  rear  wheel.  If  it  takes  a  load  or  weight  directly  on  either 
end,  then  that  end  is  not  floated.  If  either  end  is  relieved  of  all  strain 
other  than  driving  torque,  then  that  end  is  floated. 

Plain  Live. — A  plain  live  axle  is  one  in  which  each  end  of  the 
shaft  is  resting  directly  in  bearings.  The  driving  weight  as  trans- 
mitted from  the  pinion  gear  and  differential  must  be  born  by  the 
inner  end  of  the  shaft,  while  the  outer  end  of  the  shaft  carries  directly 
the  weight  of  the  entire  chassis  body  and  load.  The  advantage  of 
this  type  is  lighter  construction  and  less  play  in  parts  since  all  parts 


Fig.  37.     Live  Axle   Shafts. 
40 


Rear  Axles  and  Brakes 


41 


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.•swsrrwBiillY  ,  ;,J',-  ■ 

. ,  "1 

s^H 

^11       38 

'  ■.  ^^           ■  ""■     ''if 

i  i 

^;s-   J^     ^>^ 

s^m^^^^^^^^^ 

1  -.id 

Br. 
presse 
strong 
forgin 

1  Brake  Banc 
drum,  no  dti 

r  Bearing- 
of  all  axle 

^"^LJ 

i^ 

11. 

Si    ii           ,^a 

^ 

c 

f 

'^'  Jfi 

.23 

-<MBU[ 

i 

fi 

are  usually  keyed  together.  Some  disadvantages  are  difficulty  of 
repair  and  a  lesser  degree  of  safety  in  service.  An  axle  shaft  of  this 
type  when  broken  is  very  likely  to  let  the  wheel  come  off  and  allow 
the  axle  housing  to  drop  to  the  ground.  The  Ford  axle  is  representa- 
tive of  this  type,  and  is  a  very  sturdy  axle  for  its  weight.    In  replacing 


42 


Automotive  Trade  Training 


an  axle  drive  shaft  of  this  type,  it  is  necessary  to  remove  the  entire 
rear  axle  housing  from  the  car,  remove  the  wheels,  remove  the  torque 
tube,  and  separate  and  pull  the  housings  endwise  after  which  the 
differential  may  be  disassembled  and  the  shaft  removed. 


Fig.  39.     Three-Quarter   Floating   A.xle. 


MS 


■H^ ™  ILAjS 


Fig.  40.     Full   Floating  Axle  Type. 

Semi-Floating. — Here  the  outer  ends  are  carried  as  in  the  plain 
live,  while  the  inner  ends  rest  in  the  differential  side  gears.     These 


Rear  Axles  and  Brakes 


43 


are  carried  by  the  differential  case,  which  in  turn  is  carried  by  the 
roller  or  ball  bearings  in  which  it  rests.     This  floats  the  inner  end 

since  it  is  not  subjected  to  any 
shearing  strain.  Besides  the 
shearing  strain  on  the  outer 
end  the  shaft  is  subjected 
to  torsional  strain  and  bend- 
ing moment.  Refer  to  Fig. 
38.  In  some  cases  tension 
and  compression  may  be 
added  as  the  wheel  bearings 
do  not  take  thrust  and  the 
shaft  is  prevented  from  mov- 
ing endwise  only  by  the 
thrust  bearings  on  the  differ- 
ential case. 

Three-Quarter  Floating. — 
In  this  axle  the  inner  end  is 
floated  as  in  the  semi-floating 
while  the  outer  end  is  fitted  in 
the  center  of  the  wheel  hub, 
which  in  turn  has  a  bearing  in 
it.  This  bearing  fits  over  in- 
stead of  in  the  axle  housing 
thus  relieving  the  axle  shaft 
of  the  dead  weight  of  the  car. 
It  must  still  hold  the  wheel 
in  alignment  thus  preventing 
wobble.  It  must  also  take  all 
skidding  forces  and  side  pres- 
sure such  as  are  developed  in 
rounding  corners,  traveling 
over  uneven  roadways,  and 
skidding  into  obstructions. 
These  forces  may  be  many 
times  as  great  as  the  weight 
of  the  car  and  passengers. 
This  force  is  represented  at 
"T",  Fig.  44,  as  tending  to 
bend  the  axle  out  of  shape. 
To  actually  prevent  such 
bending  the  housing  and  shaft 
are  designed  with  a  fair  margin  of  safety.  This  type  still  carries  the 
end  strains  of  tension  and  compression  in  most  cases. 

Full  Floating.— In  this  case  the  shaft  is  relieved  of  all  loads  or 


Fig.  41.    Timken  Detroit  Worm  Drive  Truck  Axle. 


44 


Automotive  Trade  Training 


stresses  excepting  that  of  turning  the  wheel  or  torsion.  The  inner 
end  is  floated  as  described  for  the  semi-floating  while  the  outer  end 
is  floated  by  applying  two  bearings  on  the  housing  within  the  wheel 
hub,  instead  of  the  single  bearing  in  the  three-quarter  floating.  These 
two  bearings  may  be  said  to  carry  the  load  and  align  the  wheel  in 
much  the  same  manner  that  the  bearings  within  the  front  wheel  hub 
perform  their  duty.  The  shaft  serves  only  to  transmit  power  to  the 
wheel  to  turn  it. 

In  this  construction  the  inner  end  of  the  shaft  is  splined  or  milled 
square.  The  hubs  of  the  side  gears  are  machined  to  fit  these  ends, 
enough  clearance  being  allowed  to  insure  of  an  easy  fit.  That  is,  they 
may  be  pulled  out  or  forced  in  by  hand  without  driving  or  pressing. 
The  outer  end  is  either  fitted  rigidly  to  a  flange  which  is  in  turn  bolted 
to  the  road  wheels  or  is  fitted  with  a  dog  clutch.  In  either  case  the 
axle  drive  shaft  may  be  removed  without  disturbing  the  road  wheel. 

The  advantages  of  the  semi-floating  type  are  a  rigid  construction 
permitting  of  little  lost  motion  or  play  between  parts. 

It  is  not  so  quickly  or  easily  repaired  as  it  requires  the  use  of  a 
garage  press  to  remove  certain  parts.    In  some  cases  the  axle  housing 

\must    be    removed    from 
under   the   car   and   com- 
^        pletely     disassembled     to 

replace  the  shaft  or  other 
broken  parts. 


r\ 


Fig.  42.  Rear  nxles 
must  be  so  designed  as  to 
maintain  this  position  at 
the  same  time  oarrying  the 
load,  turning  the  wheels, 
and  resisting  the  skidding 
or  side   sway  effect. 

struction  the  wheel  could  not  come  off 


Fig 


Weight    of 


The  advantage  of  the 

three-quarter  floating  over 

the    plain    live    or    semi- 
floating  is  that  the  outer 

end   of  the   shaft  is   now 

relieved    of   the    shearing 

strain  due  to  the  weight 

of  the  car.     Axle   shafts 

are     less     likely     to     be 

broken,  and  if  broken  the 

car  is  less  likely  to  drop 

to  the  road.     In  one  con- 

The  disadvantages  are  about 
the  same  as  for  the  plain  live  or  semi-floating.  Replacement  of  a 
broken  shaft,  or  other  parts,  is  likely  to  entail  a  great  deal  of  work. 
In  some  cases  the  construction  permits  of  the  shaft  being  pulled  with- 
out removing  the  housing  from  the  car ;  in  others  it  does  not. 

The  advantages  of  the  full  floating  are  the  greatest  possible  factor 
of  safety  and  ease  of  replacement  of  parts.  There  is  no  possibility 
of  the  car  dropping  to  the  ground  in  case  of  a  broken  shaft.  The 
housing  is  often  of  one-piece  construction,  allowing  room  on  the  rear 


ency  to   spring  axle  as 
shown. 


Rear  Axles  and  Brakes 


45 


of  the  differential  housing  for  the  entire  differential  assembly  to  be 
removed,  after  the  shafts  have  been  removed  from  the  ends.  Quick 
repairs  and  easy  adjustments  are  thus  possible.  The  greatest  dis- 
advantage is  the  liability  of  parts  becoming  worn  v^here  a  slip  fit  is 
used  and  in  time  a  harmful  amount  of  back  lash  appears. 

Live  Axle  Types  of  Drive. — The  line  of  flow  of  power  in  the  live 
axle  is,  in  most  cases,  from  the  propeller  shaft  to  the  pinion  gear, 
pinion  gear  to  bevel  gear,  bevel  gear  to  differential  case,  differential 
case  to  differential  spider,  differential  spider  to  spider  pinion,  spider 
pinion  to  differential  side  gear,  side  gear  to  axle  shaft,  axle  shaft  to 
wheel,  wheel  to  road.  This  will  vary  somewhat  in  cases  of  special 
construction. 


Skidding    tends    to    bend    the    axle  as   shown. 

Bevel  Geai:  and  Pinion. — The  plain  bevel  gear  and  pinion  are 
used  rather  extensively  in  light  cars,  while  the  spiral  gear  and  pinion 
are  used  in  passenger  vehicles  of  the  heavier  type.     The  advantage 

secured  is  more  teeth  in  contact  at  the  same 
time,  giving  a  more  even  flow  of  power  as 
well  as  less  liability  of  fractured  teeth  due 
to  all  the  strain  coming  on  one  tooth. 

The  gear  ratio  of  pinion  and  bevel  gear 
is  rather  fixed  within  certain  limits,  four  o£ 
the  propeller  shaft  to  one  of  the  rear  axle 
shaft  being  an  average..  Almost  all  cars  of 
standard  passenger  type  would  fall  between 
three  and  one-half  to  one  which  is  a  high 
Fig.  45.  Spiral  Bevel  Gear  ratio,  to  four  and  one-half  tr  one  which 
and  Pinion.  -g  ^   low  ratio.     The  trend  however  is  to- 

ward still  lower  gear  ratios,  and  five  to  one  is  gaining  favor. 

In  the  worm  and  gear  drive  the  gear  ratio  is  much  lower  as  in 
the  Ford  where  it  is  approximately  eight  to  one. 


46 


Automotive  Trade  Training 


Worm  and  Gear. — The  worm  and  gear  is  used  in  a  large  number 
cf  truck  axles.  The  advantages  of  this  drive  are  gear  reduction  and 
ability  to  perform  continuous  heavy  duty  with  a  minimum  of  lost 
power.  Since  all  parts  are  enclosed,  well  lubricated  and  kept  free 
of  foreign  matter,  the  liability  of  failure  is  greatly  reduced.  For  this 
reason,  and  for  the  sake  of  quiet  and  increased  efficiency,  this  type  of 
drive  on  live  axles  for  trucks  has  largely  superceded  the  double  chain 
drive  on  the  dead  axle. 

Single  Chain  Drive  for  live  axles  is  practically  extinct. 

Dead  Axle  Drive. — As  mentioned  previously  the  dead  axle  has 
been  used  in  trucks  because  of  its  carrying  ability.  Formerly  a  large 
share  of  trucks  were  equipped  with  dead  axles  and  double  chain  drive. 


Fig.  46.    Two  views  of  Worm  and  Gear  as  used  in  Truck  Axle  Drive. 


Rear  Axles  and  Brakes 


47 


A  constantly  decreasing  number  of  manufacturers  are  using  the  chain 
drive.     This  is  due  to  trouble  with  the  chains  and  the  fact  that  the 


Fig.  47.     Typical  chain   drive  equipment  showing  dead  rear  axle 
chain,  sprockets  and  jack  shaft. 


Fig.    48.      Illustrating    Worm 
drive  principle. 


Fig.  49.     Sketch   showing  internal  gear 
drive   principle. 


Fig.  50.    Cross  section  of  internal  gear  rear  axle  construction. 

moving  parts  are  exposed  to  the  dirt,  dust 
and  other  foreign  materials  which  result  in 
wear  and  breakage. 

Internal  Gear  Drive. — In  this  case  a 
large  internal  gear  replaces  the  sprocket  of 
chain  drive  type  on  the  rear  wheel.  The 
power  is  transmitted  from  the  differential 
to  the  internal  gear  through  a  live  shaft 
mounted  in  conjunction  with  the  dead  axle. 
All  parts  are  enclosed  as  a  rule  to  keep  out 
dust  and  dirt  and  improve  lubrication.  As 
in  the  chain  driven  truck  the  percentage  of 
power  transmitted  to  the  road  wheel  is  high.  Trucks  of  all  ranges  of 
capacity  are  being  fitted  with  this  type  of  rear  axle. 


Fig.  51.  Double  Reduction 
Gears  as  used  in  Rear  Axle 
Drive. 


48 


Automotive  Trade  Training 


Fig.  52.     Torbensen  Internal  Gear  Rear  Axle. 


Double  Reduction  Gears. — In  some  cases  of  live  axles  double 
reduction  gears  are  used  to  so  reduce  the  gear  ratio  as  to  give  the 
proper  gearing  for  heavy  duty  work.  Part  of  the  reduction  as  in 
other  types  is  secured  by  the  difference  in  size  of  the  pinion  and  ring 

or  bevel  gears.  Another  or  added  reduc- 
tion is  secured  by  the  addition  of  the 
spur  gears  where  the  smaller  is  used  to 
drive  the  larger.  Refer  to  Fig.  51.  The 
large  spur  gear  is  mounted  in  the  place 
of  the  bevel  gear  on  the  differential. 
This  type  of  rear  axle  gearing  has  more 
parts  than  the  worm  drive  axle  of  simi- 
lar rated  capacity.  It  has  more  bearings 
and  gears  to  be  kept  in  proper  align- 
ment and  adjustment. 

Differential  Construction. — The  rear 
axle  shafts  are  independent  of  each 
other,  one  being  termed  a  right  and  the 
other  a  left-hand  shaft.  This  is  neces- 
sary to  permit  of  rounding  curves  when 
one  wheel  is  turning  faster  than  the 
other.      For    the    same   reason,    and   to 


Fig.  53.    Differential  Assembled  in 
One-half  of  the  Differential  Case. 


Rear  Axles  and  Brakes 


transmit  power  equally  to  these  wheels  even  though  it  be  at  different 
speeds,  it  is  necessary  to  provide  the  differential.  The  differential 
does  deliver  the  same  amount  of  power  to  each  whepl  irrespective  of 
the  speed.  ,  '     ,] 

To  accomplish  this  the  differential,  case  has  been  designed  to 
carry  the  ring  or  bevel  gear  from  whr^h  it  takes  the  power'  trans- 
mitted  to   it   from   the   engine   through   the^  transmission,   propeller 


Fig.  54.     Spur  Gear  Differential  as  used  in  Packard  Truck  Axle. 

shaft  and  ring  gear.  Receiving  the  power  from  the  ring  gear  the 
differential  case  transmits  it  to  the  spider  on  which  are  mounted  the 
spider  pinions.  In  the  spider  pinion  is  found  the  real  means  for 
flexible  power  transmission.  These  are  meshed  on  either  side  with 
the  two  differential  side  gears.  On  a  straight  drive  the  differential 
case,  spider,  spider  pinions,  and  side  gears  revolve  as  one  solid  mass. 
That  is,  there  is  no  internal  movement  of  any  of  the  parts  within 
the  case.  In  rounding  a  corner,  or  a  curve,  one  side  gear  is  slowed 
up  because  the  wheel  to  which  it  is  directly  connected  with  the  axle 
drive  shaft  is  slowed.  The  other  side  gear  is  speeded  up  because  the 
wheel  to  which  it  is  directly  connected  is  speeded  since  it  has  farther 
to  travel  to  round  the  curve  or  corner.  The  spider  pinions  being 
free  to  rotate  on  the  pinions  will  do  so  to  the  extent  necessary  to 
compensate  for  the  difference  in  speed.  While  still  delivering  power 
from  the  ring  gear  to  the  side  gears  as  the  differential  case  revolves, 
the  movement  of  the  pinions  within  the  case  permits,  of  the  needed 
difference  of  speed  of  the  opposed  side  gears.  If  turning  to  the; 
left  they  rotate  on  their  pivots  or  pinions  in  one  direction,  turn- 
ing to  the  right  they  will  be  caused  to  rotate  in  the  other  direction. 
Whenever  one  wheel  has  less  traction  than  the  other  it  is  likely 
to  start  spinning.     No  more  power  can  be  transmitted  to  the  other 


50 


AuTOMOTixi-:  Tkadk  Training 


Fig.   55.     Powerlock   Differential   used   to   prevent 
i)ne  wheel  spinning  in  mud  or  other  bad  going. 


wheel  than  is  needed  to  start 
and  keep  the  first  one  spin- 
ning. To  get  out  of  a  bad 
place  in  the  road,  as  in 
traveHng  through  mud,  both 
wheels  must  hold  equally  or 
have  nearly  equal  traction. 
Certain  devices  are  in  use  in 
the  differential  which  per- 
mit the  automatic  lock- 
ing of  the  differential  gears 
in  cases  where  there  is  a 
tendency  for  the  wheels  to 
spin.  This  is  almost  in- 
valuable where  heavy  haul- 
ing through  mud  is  being  done.     Refer  to  Fig.  55. 

The  action  of  the  differential  might  be  compared  to  a  team  of 
horses  hitched  to  a  double  tree  and  drawing  a  loaded  wagon.  One 
may  go  ahead  or  the  other  may  go  ahead,  but  always  when  one  goes 
ahead  the  other  falls  back.  The  differential  is  an  endless  equalizer 
or  evener. 

The  following  description  of  the  character  and  functions  of  the 
<iifferential  is  taken  from  the  Timken  Primer: 

The  differential  consists  of  a  set  of  bevel  gears  Jocated  at  the 
^renter  of  the  rear  axle.  Its  purpose  is  to  divide  the  power  trans- 
iTiitted  from  the  engine  equally  between  the  two  wheels,  and  to  do 
this  in  such  a  way  that  one  wheel  may  revolve  faster  than  the  other 
^vhen  necessary. 

In  a  wagon  the  rear  wheels  are  mounted  on  a  dead  axle  and 
revolve  independently  of  each  other.  There  is,  therefore,  no  need  for 
a  differential.  In  a  power-driven  vehicle  the  rear  wheels  must  still 
revolve  independently  and  yet  each  must  receive  one-half  of  the 
power  transmitted  through  the  rear  axle. 

To  illustrate  the  principle  in  as  simple  a  manner  as  possible  we 
show  ill  Fig.  56  an  experimental  apparatus  in  which  A — A'  are  the 

two  live  axle  shafts  to  whose 

B „j,  outer  ends  are  fastened  the 

/~^        wheels  W— W. 

Mounted  on  the  inner 
ends  of  the  shafts  A — A'  are 
the  bevel  bears  G — G'.  Sur- 
rounding these  gears  and 
concentric  with  them  is  a 
belt-driven  pulley  B. 
p.     -Q  It  will  be  clear  that  if 


Rear  Axles  and  Brakes 


51 


we  connect  the  two  gears  solidly  by  the  rods  R — R',  which  in  turn 
are  securely  fastened  in  the  web  of  the  pulley  B.  Movement  of  pulley 
B  will  cause  both  the  gears  G — G'  to  revolve  at  the  same  speed  in  the 
same  direction ;  and,  since  the  wheels  W — W  are,  like  the  gears 
G — G',  secured  to  the  shafts  A — A',  the  wheels  will  also  revolve  at 
the  same  speed  in  the  same  direction. 

Now,  to  allow  the  wheels  W — W,  and,  therefore,  the  gears 
G — G',  to  revolve  at  different  speeds,  we  remove  the  rods  R — R' 
binding  the  two  gears  together  and  substitute  for  these  rods  the 
pinions  shown  in  Fig.  57.  These  pinions  rotate  freely  on  the  web  of 
pulley  B  and  their  teeth  are  in  mesh  with  the  teeth  of  the  bevel 
gears  G — G'. 

It  is  clear  that  when  the 
pulley  B  revolves,  its  motion 
is  transmitted  through  the 
pinions  to  the  gears  G — G' 
and  on  through  the  axles 
A— A'  to  the  wheels  W— W 
just  as  it  was  transmitted  in 
the  apparatus  shown  in  Fig. 
56,  but  with  this  important 
difference — if  wheel  W  is 
now  prevented  from  revolv- 
ing, the  pinions  will  rotate 
on  the  web  and  thus  allow  the  gear  G'  to  revolve,  carrying  with  it 
axle  A'  and  wheel  W. 

If  gear  G  revolves 
slowly,  gear  G'  can  re- 
volve rapidly,  or  vice 
versa,  because  the  differ- 
enCvC  in  their  motion  is 
compensated  for  by  the 
rotation  of  pinions  P — P\ 
It  will  also  be  clear 
that  in  all  cases  the  pres- 
sure transmitted  from  the 
pulley  B  through  the  pin- 
ions P— P'  to  the  teeth 
of  the  gear  G  and  the  gear 
G'  will  be  equal,  because 
Fig:.  58.  the  distances  between  the 

centers  of  the  pinions  and  the  teeth  of  both  gears  are  always  equal. 
In  the  simplest  language  possible,  when  gear  G  remains  station- 
ary, gear  G'  and  the  pinions  roll  around,  as  it  were,  on  gear  G,  the 


Fig.  -a. 


52 


Automotive  Trade  Training 


teeth  of  the  pinions  pressing  forward  on  the  teeth  of  gears  G  and  G' 
with  equal  pressure. 

Referring  now  to  Fig.  58,  we  see  the  differential  as  actually  used 
in  the  rear  axle.  In  place  of  pulley  B  in  Figs.  56  and  57  we  have  the 
driving  gear  D,  and  instead  of  two  pinions  there  are  now  four,  but 
the  action  is  the  same  as  that  described  for  the  apparatus  in  Fig.  57. 

The  driving  gear   D   receives  the  power   from   a   beveled  gear 


Fig.  59.    Packard  Twin  Six  Brakes  and  Braking  Mechanism. 


known  as  the  driving-pinion,  the  latter  being  at  the  rear  end  of  a 
**pinion-shaft"  coupled  with  the  main  propeller  shaft  which  transmits 
the  power  from  the  engine. 

Rear  Axle  Trouble. — Most  common  of  all  rear  axle  faults  is  that 
of  broken  teeth  in  ring  or  pinion  gears.  There  are  many  causes  of 
this  trouble  chief  of  which  are  poor  driving  and  poor  adjustment  of 


Rear  Axles  and  Brakes 


53 


the  gears.  The  latter  trouble  is  one  which  will  develop  with  normal 
use  and  may  often  be  obviated  by.  a  system  of  regular  inspection. 
Care  in  the  application  of  power  will  do  much  to  save  gears. 

Transmitting  the  power  from  a  modern  high  powered  engine  to 
the  rear  axle  throws  an  almost  inconceivable  strain  on  just  one  or 
two  teeth  of  the  ring  and  pinion  gears.  There  should  never  be  less 
than  two  teeth  engaged  at  the  same  time  and  in  certain  cases  three 
teeth.  If  thrust  bearings  are  badly  worn  this  may  not  be  the  case 
and  only  one  tooth  may  be  in  contact.  When  this  condition  exists 
h  will  be  found  that  the  tooth  taking  the  load  receives  it  on  its  outer 
end  and  trouble  is  likely  to  develop  quickly.  On  a  hard  pull  the  teeth 
will  chip  and  crack.  Pieces  broken  out  come  in  between  the  other 
teeth  and  further  damage  is  caused.  In  the  latter  case  bearings  are 
very  likely  to  be  crushed. 

When  a  rear  axle  has  developed  trouble  no  further  effort  to  drive 
the  car  under  its  own  power  should  be  made  until  an  effort  is  made 
to  relieve  the  trouble.  The  car,  if  possible,  should  be,  towed  in  to 
the  service  station.  In  certain  instances  this  may  be  as  bad  or  worse 
than  driving  unless  care  is  used  to  prevent  the  axle  parts  turning. 
To  do  this  remove  axle  drive  shafts,  or,  if  the  frozen  type,  remove  the 
keys  from  the  wheel  hubs.  In  case  this  is  not  possible  a  "dolly" 
should  be  resorted  to. 

BRAKES 

The  proper  care  and  adjustment  of  brakes  is  one  too  often  over- 
looked. It  is  far  more  essential  to  stop  a  car  quickly  at  certain  times 
than  it  is  to  start  it  quickly  or  accelerate  rapidly.  The  energy  stored 
in  the  car  by  the  engine  must  ofttim'es  be  quickly  overcome  by  the 


SPEED 
RATE  PER  HOUR 

5 

Wte             Will  your  car 

.,„.-.    ^ftb       ■ 

^fe            do  this? 

20  milss  fll^^^^ 

— 20.«fK **                                                              ----- 

»^:,..    ^^ 

to 

30  miles    ^©^^ 

^ 

«.„..  ai«^' 

^ 

40  fnil««       OSSBT) 

104   M.— ^ 

mm 

I-' 

<*«, 

Showing  distances  in  which  your  car  should  stop— 

if  your  brakes  are  right                                                   1 

Fig.   60.     Chart   Showing  Brake   Efficiency   Tests. 


54 


Automotive  Trade  Training 


brakes.  The  power  generated  by  the  engine  in  climbing  a  hill  must 
be  equaled  by  the  gripping  power  of  the  brakes  in  coming  down  the 
hill.  The  engine  is  used  to  start  the  car,  to  pull  it  over  the  road,  and 
to  develop  energy.  The  brakes  are  used  to  overcome  momentum 
and  gravity. 

Braking  Surface. — The  number  of  square  inches  of  braking  sur- 
face found  on  the  brakes  of  the  car  bears  rather  a  direct  relation  to 
the  weight  and  power  of  the  car.  A  certain  factor  ot  safety  is 
allowed.  The  chart  shown  in  Fig.  60  illustrates  the  distance  which 
the  Thermoid  Rubber  Company's  engineers  have  figured  as  correct 
for  a  test  of  a  brake's  efficiency.  At  30  miles  per  hour  the  brakes 
should  be  able  to  bring  the  car  to  a  stop  in  83.3  feet.  The  speed  of 
30  miles  per  hour  represents  a  speed  of  44  feet  per  second.  Brakes 
must  act  quickly  and  positively  to  make  this  possible.  Brake  lining 
may  be  judged  in  part  by  the  construction  of  the  weave.  The  closer 
the  texture  the  more  braking  surface  actually  in  contact  with  the 
brake  drums. 

Types  of  Brakes. — The  most  generally  used  type  of  brake  is  the 
one  having  a  brake  drum  mounted  on  the  rear  wheel.  This  brake 
drum  usually  has  a  brake  band  arranged  to  contract  on  its  outer 
surface  and  another  band  or  shoe  arranged  to  expand  on  its  inside. 
Both  bands  are  lined  with  a  heat  resisting  friction  producing  material. 
This  arrangement  permits  of  tw^o  separate  braking  effects  on  the 
same  drum. 


^■T^ 

Internal 

<^^M 

||^^Fxt(rn;il  Brak<> 

tefc- 

External  Brake          /|^ 
Adjusting  Screw         /Hi 

B 

^ 

HK^  internal  Brake 
U^E^Fulcrutn  Lever 

^^^Httvrnal  Brake 

Intrrnal  Brake            m| 

nil 

H 

Huntl  l.ininft 

\^  ^^^^^^^1 

Mjj||B 

i. 

Kxternal  Brake 

x*^ 

^^BSA 

^1^ 

Adjustment 

L>.        .._.    . 

-s.  "S 

Bearing  {".a^f 
Clamp  Bolt 

Internal  BruKe 
Band  Lining 

'**'!.J?i«%    . 

Fig.  Gl.    Typical  Passenger  Car  Brakes. 


Rear  Axles  and  Brakes 


55 


Fig  62.     Brake  Drum  Mounted  on  Rear  Wheel. 


Double  Width  Drum. — In  this  case  the  brake  bands  are  assembled 
side  by  side.  Both  are  external  contracting  or  internal  expanding, 
usually  the  latter  as  this  per- 
mits of  them  being  kept 
clean  and  dry.  Grease  and 
oil  working  out  from  the 
axle  housing  is  likely  to 
cause  the  internal  type  to 
lose  its  braking  efficiency. 
When  this  happens,  the 
wheel  should  be  removed, 
the  grease  and  oil  washed  or 
burned  out,  the  drum 
cleaned,  and  then  reassem- 
bled. 

Transmission  Brakes. — In 
the  Ford  car  a  brake  drum 
is  placed  on  the  driving 
plate  which  is  always  turn- 
ing when  the  rear  wheels  are 
in  motion.  Applying  the 
brake  band  to  this  drum  by 

depressing  the  brake  lever  checks  the  speed  of  the  car.  Since  the 
gear  ratio  through  the  rear  axle  is  approximately  4  to  1,  the  braking 
effect  is  four  times  as  powerful  at  this  point  as  it  would  be  if  applied 
to  the  same  size  drum  and  band  on  the  rear  wheel.  One  bad  feature 
of  the  transmission  brake  is  the  lack  of  understanding  of  this  feature. 
A  sudden  forceful  application  of  the  brake  throws  a  tremendous  strain 
on  the  ring  and  pinion  gears  as  well  as  other  axle  parts.  At  times 
this  results  in  breakage  and  complete  loss  of  control  of  the  car. 

Another  undesirable  feature  of  the  transmission  brake  is  the 
danger  of  skidding  if  one  wheel  has  a  good  dry  road  grip  and  the 
other  is  on  ice  or  a  wet  portion  of  the  roadway.  In  this  case  the 
sudden  application  of  the  brake  which  locks  the  propeller  shaft  will 
cause  a  rapid  spinning  backward  of  the  wheel  on  the  slippery  portion 
while  the  car  skids  sidewise  or  continues  to  move  forward.  This 
action  of  the  differential  is  the  same  as  occurs  when  pulling  through 
bad  places  in  the  road  and  only  one  wheel  has  traction  and  the  other 
spins. 

The  transmission  brake  is  used  on  other  chassis  besides  the 
Ford.  It  is  used  on  a  number  of  passenger  vehicles  and  has  met  with 
a  degree  of  favor  on  commercial  cars.  The  drum  is  mounted  on  the 
outside  to  the  rear  of  the  transmission  case  and  may  be  used  either 
in  connection  with  the  foot  or  hand  brake.     Fig.  63. 

Brake  Shoes. — In  certain  cases  a  metal  shoe  without  any  lining 


56  Automotive  Trade  Training 

is  used  as  an  internal  expanding  brake.  This  type  is  almost  obsolete 
having  been,  superseded  by  the  internal  expanding  band  type  on 
which  a  fabricated  lining  is  riveted. 


Fig.  63.     Packard  Truck  Transmission  Brake  and  Drum. 

Brake  Names. — The  usual  practice  is  to  connect  the  hand  brake 
(not  emergency  brake)  to  the  internal  expanding  bands,  and  the  foot 
brake  (not  service  brake)  to  the  external  contracting  bands. 

Brake  Equalizers. — Equalizers  are  used  by  some  car  manufac- 
turers and  discredited  by  others.  The  idea  of  the  equalizer  is  to 
automatically  apportion  the  same  braking  effort  to  each  of  the  rear 
wheels  much  as  the  two  horse  evener  permits  of  each  horse  drawing 
half  the  load.  It  has  the  disadvantage  of  putting  both  brakes  of  any 
set  out  of  commission  if  there  is  a  break  on  either  side.  On  the  other 
hand  there  is  far  less  danger  of  the  brakes  gripping  or  wearing 
unevenly  in  continued  service,  and  far  less  skill  is  needed  to  secure 
a  fair  adjustment.  The  fixed  type  of  adjustment,  where  each  side  is 
actuated  in  a  fixed  relation  to  the  brake  levers,  permits  of  one  side 
being  used  after  the  other  may  have  become  broken  or  damaged  in 
such  manner  as  to  make  it  useless.  This  type  requires  expert  skill 
and  judgment  in  adjusting  for  wear.  If  one  side  is  set  to  act  more 
quickly  than  the  other  the  car  will  skid  to  the  side  whenever  the 
brakes  are  applied  suddenly. 

JOB  21.     ADJUSTING  EXTERNAL  BRAKE  BANDS. 

In  all  brake  adjustment  and  service  two  prime  points  must  be  remembered. 
The  brake  must  be  so  set  and  connected  to  the  hand  or  foot  lever  that  action 


Rear  Axles  and  Brakes 


57 


Fig.  04.     Timken  Cam  Brake. 


certain  and  sure  when  it  is  desired  to  stop  the  car.     It  is  not  so  essential  that 

the  bands  grip  the  wheels  until 
they  will  slide,  as  it  is  that  they 
will  exert  a  firm  even  pressure  all 
the  way  about  the  drum  and  give 
that  ideal  braking  effect  which  is 
just  under  the  point  needed  to  start 
the  wheels  sliding  on  a  dry  road- 
way. Once  a  wheel  starts  to  slide 
the  brakes  should  be  instantly  re- 
leased as  this  is  a  dangerous  con- 
dition and  the  momentum  of  the 
car  will  carry  it  much  farther  with 
the  wheels  sliding  than  when  they 
are  rolling  over  the  roadway  with 
the  proper  gripping  effect  on  it. 

The  second  point  to  be  remem- 
bered is  that  the  brakes  must  be 
so  set  that  they  will  not  drag  and 
consume     a     needless     amount     of 

power  which  may  result  in  burned  brakes  and  an  overheated  motor. 

Practically  all  brakes  operating  on  the  rear  wheel  drums  are  of  the  same 

general   construction.     The   adjustments  are   to   be   made   along  the   following 

lines: 

1.  Jack  up  the  rear  wheels  so  that  each  is  free  of  the  floor.  It  is  essential 
to  have  both  wheels  free  at  the  same  time.  Since  two  jacks  leave  the  job  a 
little  unsteady  it  is  well  to  block  up  one  side  with  wood  blocks,  a  trestle,  or 
like  arrangement.  This  permits  of  shaking  and  pulling  on  the  brake  parts 
without  danger  of  the  car  dropping  from  the  jacks. 

2.  Inspect  the  entire  braking  mechanism  to  learn  its  general  condition 
and  see  where  the  lack  of  proper  braking  effect  lies. 

3.  Note  if  the  brake  pedal  has  the  proper  travel. 

4.  Note  if  the  brake  band  is  worn  badly. 

5.  Note  if  the  brake  drum  has  any  grease  on  it. 

6.  Note  whether  the  brake  band  fits  evenly  around  the  drum. 

7.  Have  a  helper  press  the  foot  pedal  forward,  noting  whether  the  upper 

and  lower  halves  are  gripping 
equally,  or  whether,  due  to  poor 
adjustment,  the  upper  or  lower 
half  of  the  band  only  is  opera- 
tive. 

8.  Have  the  helper  set  the 
pedal  at  a  certain  point,  while 
each  wheel  is  tested  to  see  if  the 
braking  effect  is  properly  equal- 
ized. 

9.  Inspect  all  springs  to  see 
that  they  are  operating  properly. 

10.  Having  made  the  above 
inspection  the  brakes  may  be 
adjusted  where  needed.  If  the 
entire  job  must  be  gone  over 
proceed  as  follows: 

11.  Set  the  adjusting  screw 


Fig 


Timken   Toggle    Brake. 


58 


Automotive  Trade  Training 


at  the  rear  of  the  brake  band  until  the  clearance  between  the  drum  and  band 
is  from  1/64"  to  1/32".     This  will  insure  the  brake  being  free  at  that  point. 

12.  Adjust  the  center  top  adjustment,  if  one  is  provided,  to  have  the  same 
clearance. 

33.  Adjust  the  center  bottom  adjustment,  if  there  is  such,  until  the 
clearance  there  is  the  same  again. 

14.  At  the  front  end  of  the  lower  half  is  usually  found  a  pair  of  lock  or 
jam  nuts.  These  should  now  be  adjusted  until  the  proper  clearance  of  1/^64"  to 
1/32"  is  shown  on  all  of  the  lower  half  of  the  band. 

15.  The  upper  end  of  the  brake  band  is  now  drawn  down  by  means  of 
the  thumb  nut  until  the  proper  clearance  shows  all  the  way  along  the  top  half 
of  the  band. 

16.  With  the  band  properly  fitted  to  the  drum  the  next  adjustment  to 
make  is  that  of  the  pull  rods  and  clevises.  It  is  very  essential  in  making 
adjustments  on  the  pull  rods  not  to  bring  the  levers  on  the  equalizing  bar  at 
the  center  of  the  car  past  centers.  Rather  leave  them  back  of  center  so  that 
the  application  of  the  brake  fully  will  leave  them  in  a  vertical  position.  For 
this  reason  it  is  best  to  take  up  the  rear  rod  rather  than  the  forward  one.  Fig. 
66  shows  the  right  and  wrong  method. 


RIGHT  WAY 


Fig.   G6.     Methods   of   Adjusting   Pull    Rods    (Hudson). 


JOB  22.     ADJUSTING  INTERNAL  EXPANDING  BRAKES. 

Two  types  of  internal  expanding  brakes  are  in  common  use.  The  first  and 
most  common  is  the  type  expanded  by  means  of  a  cam,  and  the  second  is  the 
toggle  type.  Either  type  may  or  may  not  be  adjustable  within  the  drum. 
Where  no  adjustment  is  provided  within  the  drum  all  adjustment  to  take  up 
wear  must  be  made  on  the  clevises  under  the  floor  boards  or  on  the  pull  rods. 
In  doing  this  work  it  is  necessary  to  proceed  as  follows: 

1.     Jack  and  block  both  sides  of  the  axle  to  hold  the  wheels  free  of  the 


floor. 

2. 

3. 

4. 

5. 
come 


Remove  the  wheels.     (Refer  to  Jobs  21  and  29.) 
Inspect  the  lining  and  free  it  of  all  grease  or  oil. 

Note  whether  an  inner  adjustment  is  provided  as  that  shown  in  Fig.  65. 

Where  an  inner  adjustment  is  provided  it  should  be  set  so  as  to  over- 

any   unnecessary   clearance.     The   wheel   will   have   to   be   placed   on  a 


Rear  Axles  and  Brakes 


59 


number  of  times  possibly,  to  secure  just  the  proper  adjustment.     It  is  well  to 
have  the  pull-rod  clevis  dropped  for  this  work. 

6.  Next  adjust  the  pull-rod  clevis  until  all  the  slack  is  out  of  it,  and  with 
the  lever  in  "off"  position  the  clevis  pin  may  be  replaced. 

7.  Test  the  wheel  for  drag. 

8.  Test  the  wheel  for  braking  effect. 

9.  In   case   there   is   no   inner   adjustment   the   pull    rods   alone    must   be 


Fig.   67.     Dodge    Rear   Axle   and   Brake   Adjustments. 

depended  on.     When  they  no  longer  hold,  and  permit  of  no  further  adjustment, 
it  is  usually  necessary  to  reline  the  bands  or  shoes. 

10.  It  sometimes  happens  that  the  adjustment  is  entirely  up  and  that  the 
lining  is  still  good.  To  provide  more  take-up  the  brake  pull  rods  are  removed 
and  additional  threads  cut  on  them. 

11.  Test  wheels  for  braking  effect.  Make  certain  that  the  brakes  are 
sufficiently  firm  to  hold  the  car  on  any  grade.  Note  also  any  tendency  to  drag 
or  to  grab. 

JOB  23.     REMOVING  GREASE  AND  OIL  FROM  BRAKES. 

1.  Jack  up  the  rear  axle.     Block  car  to  niake  secure. 

2.  Pull  wheels.     (Job  29.) 

3.  Remove  both  inner  and  outer  brake  bands  if  such  are  used. 

4.  Take  the  bands  to  the  bench  or  cleaning  trough  where  they  may  be 
cleaned  with  gasoline  or  kerosene. 

5.  Learn  the  cause  of  the  grease  working  out  from  the  axle  housing  into 
the  brake  drum. 

6.  If  the  housing  has  oil  above  the  specified  level  which  is  even  with  the 
filling  plug,  or  about  one-third  full  in  most  cases,  it  must  be  allowed  to  drain 

off.  .  .  , 

7.  If  the  trouble  is  with  the  felt  washers  in  the  bearmg  mountmg  they 

must  be  replaced. 


60 


Automotive  Trade  Training 


8.  Sometimes  grease  will  work  under  or  through  bearing  races.  A  soft 
rag  wrapped  properly  under  the  bearing  cup  will  sometimes  correct  the  trouble. 

9.  Where  the  brake  lining  is  of  a  porous  nature  the  oil  is  likely  to  saturate 
the  lining  to  such  an  extent  that  it  is  impossible  to  wash  it  out.  In  this  case 
the  gasoline  torch  or  the  welding  flame  may  be  used  to  heat  the  lining  and  thus 
dry  it  out.  As  the  grease  or  oil  is  forced  out  by  the  heat  it  will  burn  with  a 
yellowish  flame. 

10.  With  a  very  hot  flame  of  this  nature  it  is  quite  possible  to  burn  the 
lining.  In  no  case  should  it  be  heated  until  it  starts  to  glow.  In  fact,  heating 
at  all  is  to  be  discouraged  except  in  the  case  of  linings  so  saturated  that  nothing 
else  will  correct  the  trouble.  If  this  work  is  done  with  the  bands  in  place  the 
operator  should  have  a  fire  extinguisher  at  hand. 

JOB  24.     RELINING  BRAKES. 

The  job  of  lining  brakes  is  readily  done  if  a  few  vital  points  are  remem- 
bered. Selection  of  brake  lining  is  a  matter  for  the  car  owner  to  settle  but  he 
should  be  encouraged  to  put  on  a  good  standard  product.  Experienced  drivers 
know  so  well  the  value  of  good  lining  and  good  brakes  that  they  are  willing 
to  pay  the  price  for  them. 

1.  Jack  up  the  car  and  block  securely. 

2.  Pull  the  rear  wheels.  Place  parts  where  they  will  be  safe  and  kept  free 
from  dirt,  especially  the  bearings. 

3.  Remove  the  brake  bands  or  shoes. 

4.  Measure  the  width  of  the  old  lining  and  estimate  the  probable  thickness 


Fig.    68.     :Brake    Lining    Surfaces 


of  it  in  its  original  form.     Consult  the  manufacturers  specifications  if  in  doubt. 

5.  Measure  the  length  and  order  the  exact  amount  needed. 

6.  Remove  all  old  lining  from  all  the  bands.     Remove  all  old  rivets,  rust, 
dirt  and  grease. 

7.  Fit  in  and  cut  all  pieces  for  the  bands. 

8.  In  lining  the  internal  bands  or  shoes  the  lining  is  first  placed  on  the 


Rear  Axles  and  Brakes 


61 


band,  drawn  tight  and  clamped  at  each  end.  If  no  clamps  are  at  hand  several 
stove  bolts  may  be  used  to  hold  the  lining  in  position.  Next  take  a  punch  to 
mark  the  lining,  marking  from  the  inside  out,  unless  it  is  possible  to  use  the 
hand  drill  to  drill  immediately. 

9.  Remove  the  marked  band  and  drill  each  point  marked  with  a  5/32"  or 
3/16"  drill  depending  on  the  size  rivet  used. 

10.  Countersink  for  rivet  heads,  if  necessary,  and  replace  the  lining  in 
position. 

11.  In  riveting  where  solid  rivets  are  used,  as  they  are  in  most  cases,  the 
head  should  be  rested  on  the  end  of  a  blunt  punch  or  bolt  while  the  end  is 
being  riveted  over, 

12.  Do  not  attempt  to  hammer  the  end  over  flat,  but  give  it  a  few  sharp 
blows  to  upset  it  in  the  band  and  form  a  burr  too  large  to  prevent  it  being 
pulled  out. 

13.  In  selecting  rivets  for  any  particular  piece  of  work  they  should  extend 
through  the  band  a  distance  equal  to  the  thickness  of  the  rivet. 

14.  Under  no  circumstances  should  any  but  a  soft  copper  rivet  be  used. 
These  may  be  secured  from  the  supply  houses. 

15.  In  lining  the  external  bands  care  must  be  used  to  make  the  lining  lay 
close  to  the  bahd.  In  no  case  must  it  be  permitted  to  buckle,  nor  must  it  be 
too  short  else  the  lining  will  not  conform  to  the  curve  of  the  band  and  drum, 
with  the  result  that  it  is  impossible  to  prevent  the  brakes  from  dragging. 

16.  Some  mechanics  make  the  practice  of  riveting  each  end  to  the  lining 
in  place  as  the  first  step,  allowing  a  slight  buckle  of  the  lining  inward.  After 
the  ends  are  secured  this  small  buckle  is  hammered  out  thus  insuring  an  even 
laying  lining.  This  buckle  must  not  be  left  until  all  but  a  few  rivets  are  in,  or 
difficulty  will  be  experienced  in  getting  it  out. 

17.  The  careful  mechanic  will  make  certain  the  rivet  heads  are  all  below 
the  surface  of  the  lining. 

JOB  25.     SQUEAKING  BRAKES. 

Most  cases  of  brake  squeaks  can  be  removed  by  properly  aligning  the  band 
on   the   drum   and   readjusting.     In    some    cases   the    trouble   can    not   thus   be 


Fiff 


62 


AUTOMOriNK    TkADI*:    'rKAlMNC, 


remedied.  Hudson  engineers  recommend  the  method  illustrated  in  Fig.  69  for 
correcting  this  fault.  In  fact,  the  practice  of  leaving  out  a  piece  of  lining  at 
the  rear  of  the  band  when  relining  brakes  is  meeting  with  much  favor.  To 
remove  the  objectionable  piece  proceed  as  follows. 

1.  Set  the  brakes. 

2.  Select  a  drill  just  slightly  smaller  than  the  thickness  of  the  lining. 

3.  Drill  between  the  band  and  the  drum  at  the  two  points  indicated. 

4.  Remove  the  piece  of  lining  thus  cut  loose. 

JOB  26.     ADJUSTING  PACKARD   TWIN   SIX   FOOT  BRAKES. 

Refer  to  Figs.  70  and  77. 

The  foot  pedal  is  connected  with  the  external  brake  bands.  The  clearance 
allowed  between  the  bands  and  the  drum  is  1/32"  all  the  way  around. 

1.  Adjust  the  nut  on  the  rear  support  until  the  clearance  is  proper  at  that 
point. 

2.  Adjust  the  two  nuts  on  the  shank  of  the  clevis  just  below  the  eyebolt 
at  the  front  of  the  brake  until  the  distance  between  the  lower  half  of  the  brake 
band  and  the  drum  is  also  3^2". 

3.  Adjust  the  "T"  handle  which  operates  the  adjusting  screw  until  there  is 
a  clearance  of  3^2"  between  the  upper  half  of  the  band  and  the  drum. 

4.  To  check  for  equalization  make  sure  that,  with  brakes  released,  the 
brake  pedal  connecting  rod  is  so  adjusted  that  the  stops  on  the  equalizer  levers 
just  clear  the  rear  of  the  rear  cross  channel  when  the  pedal  is  against  the  floor 
board.  The  connection  from  the  brake  cross  shaft  to  the  rear  axle  should  be 
so  adjusted  that  the  clevis  pins  at  the  upper  end  of  the  brake  toggle  levers 
clear  the  band  by  %"  on  each  wheel.     This  insures  proper  equalization. 

The  equalizer  bar  should  ordinarily  be  set  in  the  upper  holes  of  the 
equalizer  levers.  For  city  and  for  moderate  speed  driving  they  may  be  set  in 
the  lower  holes  thus  reducing  the  effort  required  to  obtain  a  given  braking 
result. 


Fig.  70.    Packard   Twin   Six,   Rear  Axle  and  Brakes. 


Rear  Axles  and  Brakes  63 

JOB  27.     ADJUSTING  PACKARD  TWIN  SIX  HAND  BRAKES. 

The  hand  brake  lever  controls  the  internal  expanding  brake  shoes.  These 
must  be  so  adjusted  that  when  applied  there  is  the  same  resistance  on  each  rear 
wheel.     Make  the  following  adjustments: 

1.  Make  all  adjustments  for  wear  on  the  side  pull  rods  connected  to  the 
cam  shaft  levers. 

2.  By  removing  the  rear  wheel  the  hand  brake  band  can  be  set  concentric 
Avith  the  brake  drum  by  means  of  the  set  screw  at  the  rear.  The  band  should 
just  clear  the  drum  at  this  point. 

3.  The  hand  lever  should  be  in  the  sixth  notch  from  the  front  when  the 
brakes  are  applied. 

JOB  28.     SPLIT  HOUSING  TYPE  REAR  AXLE  OVERHAUL. 

Certain-  of  the  lighter  cars  use  a  rear  axle  having  the  housing  bolted 
together  in  the  center  rather  than  the  one-piece  construction.  This  construc- 
tion is  also  found  in  a  few  of  the  heavier  cars  and  some  of  the  trucks. 

1.  Jack  up  the  car  and  block  up  under  the  frame  to  hold  all  the  weight 
free  of  the  axle.     If  a  hoist  or  crane  is  available,  it  should  be  used  for  this  work. 

2.  Drop  all  brake  rods,  radius  rods,  spring  clips,  etc.,  which  will  in  any 
manner  prevent  the  axle  being  removed  as  a  unit. 

3.  If  the  car  cannot  be  raised  high  enough  to  permit  the  axle  being  pulled 
out  to  the  rear,  without  the  wheels  striking  the  fenders,  the  wheels  must  be 
pulled  and  the  housing  dropped  to  the  floor.     (Refer  to  Job  30.) 

4.  Place  the  axle  housing  on  the  horses,  or  rack,  and  remove  the  propeller 
tube  and  shaft. 

5.  Remove  the  bolts  holding  the  two  half  housings  together. 

6.  Pull  these  away  from  the  axle  shaft  assembly. 

7.  The  next  step  is  to  open  up  and  inspect  the  differential,  noting  carefully 
the  method  of  assembly. 

8.  Very  frequently  the  differential  side  gears  are  pressed  onto  the  inner 
end  of  the  axle  shafts.  To  remove  them  it  is  necessary  to  press  or  drift  the 
side  gear  downward  a  bit  to  remove  the  split  retainer  ring.  This  is  usually  at 
a  point  close  to  the  inner  end  of  the  axle  shaft.  When  the  split  ring  is  removed 
the  side  gear  may  be  pressed  or  drifted  oflf  the  axle  shaft. 

9.  The  parts  should  all  receive  careful  inspection  and  those  showing  signs 
of  wear  should  be  replaced. 

10.  In  reassembling  the  utmost  care  must  be  used  to  have  all  parts 
properly  assembled.  In  some  cases  the  gear  adjustment  is  a  fixed  nature. 
That  is,  no  provision  is  made  for  taking  up  wear.  If  the  parts  are  otherwise  in 
540od  condition,  but  an  unwarranted  amount  of  backlash  is  evident,  it  may  be 
removed  by  the  judicious  use  of  shims.  The  most  common  method  is  to  place 
a  metal  shim  back  of  the  thrust  bearing  which  holds  the  bevel  gear  in  contact 
Avith  the  pinion  gear.  A  number  of  careful  tests  are  necessary  to  insure  the 
proper  clearance  of  .005"  to  .008"  between  these  gears. 

11.  Pack  all  parts  with  a  medium  cup  grease  or  apply  heavy  oil  to  them 
so  that  lubrication  is  immediate  when  the  car  goes  into  service. 

12.  Reassemble  under  the  car,  being  careful  to  have  each  and  every  part 
in  proper  position  and  properly  secured  with  cotter  keys  and  lock  washers. 

13.  When  reassembling  the  wheels  on  the  axle  care  must  be  used  to  have 
the  bearings  properly  adjusted  and  the  brakes  properly  fitted. 

14.  It  is  a  good  plan  to  go  over  each  part  of  the  work  as  a  matter  of  final 
inspection,  and  then  again  after  a  few  days  of  service  testing  all  nuts  with  the 
wrench  to  make  certain  they  are  snug.     This  refers  to  externally  located  parts. 


64 


Automotive  Trade  Training 


Fig.  71.     Overland  Four   Rear  Axle  and   Brake  Adjustments. 


Brake  Linings 


Axle  Shaft 
Inner 
Brake  Cam 


Rear  Axles  and  Brakes 


65 


JOB  29. 


OVERHAULING  REAR  AXLES  OF  SINGLE  PIECE  HOUSING 
CONSTRUCTION. 


In  most  cases  of  full  floating,  and  in  some  cases  of  other  axles,  the  housing 
is  a  pressed  steel  construction,'  so  arranged  that  the  differential  assembly  may 
be  put  in  from  the  front  or  rear  of  the  housing  and  the  axle  shafts  from  the 
ends. 

In  this  construction  it  is  seldom  necessary  to  remove  the  axle  from  the  car. 
The  usual  plan  of  overhaul  in  this  case  is  to  run  the  car,  or  lift  it,  onto  blocks 
which  will  give  sufficient  room  for  the  workman  to  get  under  it  and  at  the 
inspection  plate  to  the  re^r  of  the  axle  housing.  After  the  car  is  in  position, 
properly  secured  to  prevent  moven-'-.nt,  proceed  as  follows: 

1.  Remove  axle  drive  shafts.     (Job  30.) 

2.  Remove  inspection  plate  at  center  rear  of  housing.     (Fig.  72.) 


Fig.  72. 


Method  of  opening  up  axle  for  inspection   and  adjustment 
of  the  bevel  gear. 


3.  If  the  differential  is  to  be  removed  next  release  the  four  holding  studs 
or  nuts. 

4.  This  permits  of  the  caps  being  removed  and  the  entire  assembly  being 
lifted  out.     Fig.  73  shows  the  assembly  out  but  the  caps  and  nuts  in  position. 

The  same  figure  shows  the 
notched  adjusting  rings  by 
means  of  which  the  differ- 
ential assembly  is  brought 
into  proper  relation  to  the 
pinion  gear. 

5.  The  differential 
and  bearings  may  now  be 
taken  apart  and  inspection 
and  replacements  made. 

6.  The  pinion  gear 
assembly  should  next  be 
inspected  and  all  worn 
parts  replaced. 

7.  Replace  the  pinion 
gear  assembly  in  position. 

8.  Replace  the  differ- 
ential assembly  in  posi- 
tion. 


Fig.  73.     Differential  assembly  and  mounting. 


9.  Adjust  these  as  suggested  in  Job  31. 

10.  Replace  axle  shafts. 

11.  Replace  the  inspection  cover  and  fill  with  lubricant  to  the  proper  level. 

12.  Test.     Make  final  inspection  and  adjustments. 


66 


Automotive  Trade  Training 


Dll      SpJlift  ; 


R  ■       Hi-vei  Qtiii  DiL  Beaiusg 


Fig.  74.     Marmon   Rear  Axle  Parts  opened  up   for  inspection. 


JOB  30.     PULLING  REAR  WHEELS. 

The  student  should  first  study  the  external  construction  to  note  the  type 
of  axle  being  worked  on  and  thus  decide  what  is  necessary  to  remove  the  wheel. 
Note  the  following  points: 

1.  If  the  hub  cap  is  a  comparatively  small  one  and  the  hub  bolts  have  the 
rounded  heads  exposed  the  hub  is  of  the  socalled  fixed  type.  The  wheel  is 
keyed  to  the  shaft  on  a  taper  joint.     To  remove  proceed  as  follows: 

a.  Jack  up  the  axle  to  free  the  wheel. 

b.  With  a  hub  wrench  remove  the  hub  cap. 

c.  Remove  the  cotter  key  and  the  castellated  nut. 

d.  Attempt  to  pull  the  wheel  by  hand.  Failing  in  this,  put  on  a  wheel 
puller  which  may  be  of  the  hub  type  which  is  scr6wed  onto  the  threaded  end 
of  the  hub  and  locked  in  position  with  a  set  screw,  or  it  may  be  of  the  heavier 
type  which  is  adjustable  to  fit  over  the  center  of  the  wheel  back  of  the  spokes 
or  hub.  When  properly  fitted,  in  either  case  the  wheel  is  pulled  by  drawing  on 
the  center  screw  of  the  puller. 

e.  If  the  wheel  proves  stubborn  it  may  be  necessary  to  jar  the  set  screw 
of  the  puller  or  the  hub  of  the  wheel  to  break  its  grip. 

f.  If  no  wheel  puller  is  at  hand,  several  scantlings  or  two-by-fours  may  be 
used  to  pry  outward  on  the  wheel,  at  the  same  time  giving  the  end  of  the  axle 
shaft  a  sharp  blow  with  a  bronze,  lead  or  wood  mallet. 

g.  Under  no  circumstances  should  the  end  of  the  shaft  be  driven  on 
without  proper  pressure  being  applied  at  the  rear  of  the  wheel,  nor  should  a 
steel  faced  hammer  be  used  on  the  end  of  the  shaft. 

2.  If  the  hub  cap  is  small  and  the  hub  flange  is  held  on  by  means  of  a 
number  of  hexagon  nuts  visible  from  the  outside,  proceed  as  follows: 

a.  Remove  the  hexagonal  nuts,  six  or  eight  in  number. 

b.  Gripping  the  hub  cap  and  flange  firmly,  work  it  loose  and  pull  ofif  the 
flange  when  the  shaft  will  be  drawn  with  it. 

c.  Remove  the  locking  device  and  then  the  nuts  and  bearing,  after  which 
the  wheel  may  be  removed  by  hand. 


Rear  Axles  and  Brakes 


67 


d.  Be  very  careful  to  note  the  proper  assembly  of  parts  and  preserve  the 
sarings  free  of  all  dirt  and  grit. 

e.  When  replacing  the  bearings  they  should  be  cleaned  and  packed  with 
ean  cup  grease. 

3.  When  the  hub  cap  is  large  the  first  step  is  to  remove  it,  after  which 
le  axle  drive  shaft  may  be  pulled  by  hand  and  the  wheel  removed  as  suggested 
nder  2. 


Fig.  75.     Reo   Rear  Axle   Adjustment. 


JOB  31.     ADJUSTING  REAR  AXLE  BEVEL  AND  PINION  GEARS. 

For  the  most  efficient  operation  as  well  as  for  quietness,  it  is  very  essential 
lat  the  pinion  and  bevel  be  properly  meshed.  If  they  are  set  too  close 
igether  the  axle  will  be  noisy  and  growl  or  hum.  Straight  bevel  gears  are 
ore  prone  to  be  noisy  than  the  spiral  bevel.  The  clearance  recommended  for 
•operly  adjusted  gears  is  from  .005"  to  .008". 

Fig.  76  shows  the  results  of  proper  and  improper  methods  of  adjusting 
ese  gears.     A  careful  study  of  the  chart  is  well  worth  the  student's  while. 


68 


Automotive  Trade  Training 


There  are  three  main  reasons  for  rear  axle  adjustments.  They,  with  the 
proper  method  of  correcting  same,  are  given  below. 

To  Take  Up  Wear  In  Bearings: 

1.  Loosen  the  lock  on  the  holding  bolts.  This  is  usually  a  wire,  or  cotter 
keys. 


Rear  Axles  and  Brakes 


69 


2.  Turn  the  adjusting  rings  until  all  perceptible  looseness  is  removed,  but 
the  differential  or  pinion  shaft  is  running  free. 

3.  Set  and  lock. 

To  Take  Out  Excessive  Backlash: 

1.  Release  the  locking  devices  on  each  side  of  the  differential. 

2.  Turn  both  adjusting  rings  at  the  same  time  so  as  to  allow  the  entire 
differential  to  be  moved  toward  the  pinion. 

3.  Allow  the  clearance  recommended  above. 

4.  Lock  and  secure  parts. 


Fig.  77. 


Packard  Rear  Axle.    Note  method  of  adjusting  pinion 
gear  and  bevel  gear. 


To  Remove  Noise  and  insure  Proper  Meshing  of  Teeth: 

1.  If  the  gears  are  new  they  should  be  set  so  that  the  rear  edges  of  the 
teeth  are  even.  This  is  effected  through  the  adjustment  of  the  pinion  gear 
shaft  forth  and  back. 

2.  Take  up  any  play  in  the  bearings. 


70 


Automotive  Trade  Training 


3.  Move  the  gear  in,  test  for  noise  by  running  the  engine. 

4.  Move  gear  outward,  tes*^^  again  for  noise. 

5.  Allow  it  to  remain  at  the  quietest  point  and  secure  by  tightening  and 
locking  the  holding  screws. 

6.  Any  excessive  backlash  must  be  removed  by  adjusting  the  differential. 

7.  When  .005"  backlash  is  allowed  a  barely  perceptible  amount  of  motion 
is  detected  between  the  gears. 

8.  If  it  is  desired  to  test  the  actual  line  of  contact  of  the  pinion  on  the 
bevel,  which  is  the  most  certain  method,  the  pinion  must  be  coated  with  bearing 
blue  and  the  marks  left  on  the  bevel  gear  noted.  Or,  the  blue  may  be  applied 
to  the  bevel  and  the  results  of  driving  it  with  the  pinion  noted  by  the  marks  left 
in  the  blue. 

9.  Ordinarily  gears  should  be  inspected  each  5,000  to  10,000  miles,  and 
adjusted  if  necessary. 

10.  An  axle  which  grows  suddenly  noisy  should  be  inspected  and  adjusted 
immediately.  This  will  frequently  effect  a  marked  saving  of  expense  for  new- 
parts. 

JOB  32.  REMOVE  FORD  REAR  AXLE  FROM  CAR. 


1.  Jack  up  the  car. 

2.  Remove  hub  caps. 

3.  Remove  cotter  keys  and  nuts. 

4.  Secure  a  wheel  puller  from  the  tool  room,  turn  on  the  hub  and  lock 
with  the  screw.  Turn  the  set  screw  onto  the  spindle  and  thus  draw  the  wheel 
off  the  tapered  spindle. 

5.  Remove    4  bolts   at   the   universal   ball 
cap. 

6.  Disconnect   the   brake    rods. 

7.  Remove  nuts  from  the  spring  perches. 

8.  Raise  the  frame  of  the  car. 

9.  Remove   the  rear  axle. 


JOB     33. 


REMOVING     UNIVERSAL 
FROM  AXLE. 


1.  Remove    two   plugs   from   the   top   and 
bottom  of  the  ball  casting. 

2.  Turn    the    shaft    until    the    pin    comes 
opposite  the  hole. 

3.  Drive  out  the  pin. 

4.  Pull  or  force  the  joint  from  the  hous- 
ing. 


Fig.    7S.      Timkeji     Bevel    Gear 
Mounting  in  tlie  Rear  Axle. 


JOB  34.     DISASSEMBLING  FORD  REAR  AXLE.     Fig.  79. 


1.  Remove  the  radius  rod  nuts  on  the  front  end. 

2.  Remove  the  nuts  from  the  studs  holding  the  rear  of  the  torque  tube  to 
the  differential  housing. 

3.  Remove  differential  housing  bolts. 

4.  Working  over  the  pan  to  catch  the  grease  pull  the  parts  apart. 

5.  Be  very  certain  to  place  all  nuts,  bolts,  etc.,  where  they  will  be  safely 
held  for  reassembly. 

6.  Clean  the  parts  of  grease. 


Rear  Axles  and  Brakes 


71 


JOB  34-A.     DISASSEMBLING  FORD  AXLE  DIFFERENTIAL. 
INSPECTION  AND  REASSEMBLY.     Fig.  79. 


1.  Remove  all  studs  holding  parts  together. 

2.  Note  as  parts  come  apart  how  they  are  assembled. 

3.  Clean  grease  from  them. 

4.  Study  these  differential  gears  to  see  how  they  function. 

5.  Which  are  the  spider  gears? 

6.  Which  are  compensating  gears? 

7.  How  are  spider  gears  held  on  the  spider?     What  work  does  the  spider 


do,  if  any? 


t2  Automotive  Trade  Training 

8.  Remove  one  compensating  gear  by  forcing  or  pressing  down  on  the 
shaft  far  enough  to  permit  the  small  split  ring  to  be  removed,  and  then  press 
gear  off  shaft. 

9.  What  prevents  the  shaft  and  gear  from  turning  separately? 

10.  Reassemble  differential,  replacing  any  worn  or  defective  parts. 

11.  Have  them  inspected. 

12.  Reassemble  the  rear  axle  housing.  Great  care  must  be  used  to  see 
that  the  thrust  bearings  are  properly  assembled,  otherwise  the  housing  will  be 
broken.     Cup  grease  will  hold  them  in  place. 

13.  Have  them  inspected. 

14.  Remove  the  pinion  gear  from  the  propeller  shaft  by  removing  the 
cotter  and  nut,  after  which  the  pinion  may  be  driven  off,  using  a  soft  metal 
hammer  or  a  block  of  wood. 

15.  Reassemble  the  propeller  shaft  in  the  torque  tube  and  bolt  it  to  the 
rear  axle  housing. 

16.  Have  it  inspected. 

17.  Place  it  under  the  car  and  fasten  it  in  place. 

18.  Place  on  the  wheels.  Set  up  the  nut  quite  snug.  Inspect  after  30 
days  to  see  if  it  is  still  tight.    Tighten  if  necessary. 


CHAPTER  4 
CLUTCHES,  TRANSMISSIONS  AND  UNIVERSALS. 

Transmission  Units.— Along  with  all  other  units  of  chassis  design, 
the  transmission  has  become  standardized  in  the  use  of  the  sliding 
gear  selective  type.  The  most  popular  form  is  the  four  speed  selec- 
tive where  three  speeds  forward  and  one  reverse  are  provided.  The 
selective  progressive  is  in  use  to  a  slight  extent,  as  are  also  the  five 
speed  selective  and  the  planetary  and  friction  disk  drive.  Of  the 
progressive  and  friction  disk  little  need  be  said  as  they  are  considered 
obsolete. 

Progressive. — In  the  use  of  this  type  of  gear  box  for  the  operator 
to  obtain  certain  speeds,  it  is  necessary  that  the  gears  must  be  meshed 
with  and  passed  through  other  gears  than  those  giving  the  desired 
speed.  For  instance,  it  is  necessary  to  pass  through  second  speed 
to  reach  high  from  a  neutral  position,  and  from  high  to  intermediate, 
to  neutral  position,  to  low,  and  through  it  to  reach  reverse.  This 
system  is  noisy  and  troublesome. 

Friction  Disk. — A  large  disk  is  mounted  on  the  rear  of  the  trans- 
mission shaft.  Against  its  polished  sides  or  steel  surface  a  friction 
wheel  is  forced.  The  closer  the  friction  wheel  is  brought  to  the  cen- 
ter of  the  disk,  the  slower  the  speed.  The  farther  from  the  center 
toward  the  edge,  the  faster  or  higher  the  speed.  If  the  friction  wheel 
is  brought  to  center  position  it  is  in  neutral  and  if  past  center  reverse 
is  obtained. 

Progressive  Selective. — In  this  case  all  gears  or  speeds  may  be 
selected  at  will,  excepting  only  reverse,  to  reach  which  it  is  necessary 
to  pass  through  low  again.  This  provision  is  necessary  as  four 
speeds  forward  are  provided. 

Selective. — The  selective  is  the  nearest  approach  to  the  ideal. 
Any  gear  or  speed  may  be  selected  at  will  by  the  driyer,  whether  it 
be  low,  intermediate,  reverse,  or  high.  Reverse  may  be  reached 
directly  from  high  as  is  the  need  when  stopping  to  turn.  Inter- 
mediate, or  high,  may  be  entered  immediately  as  is  desirable  in  start- 
ing down  a  grade. 

The  need  of  change  gears  in  the  motor  car,  either  passenger  or 
truck,  is  a  matter  of  fact.  Even  the  multiple  cylinder  engine  as 
lepresented  by  the  twin  types  does  not  develop  sufficient  power  at 
slow  speeds  to  warrant  attempting  to  do  without  them.  The  inherent 
nature  of  the  gasoline  engine  is  such  that  it  does  not  develop  its  best 
power  at  speeds  commensurate  with  starting  on  high  gear.  This  is 
brought  out  in  the  chapter  on  engines. 

Gear  Ratio. — In  figuring  gear  ratios  it  is  best  to  remember  that 

73 


u 


Automotive  Trade  Training 


in  practically  every  case  what  is  known  as  high  gear  is  a  direct  drive 
through  the  gear  box  or  transmission  case.  Although  the  gears  are 
turning,  the  counter  shaft  is  not  carrying  any  load  as  it  must  at  all 
other  speeds.  The  countershaft  is  so  designed  as  to  be  kept  turning 
in  order  to  facilitate  speed  changes  and  provide  proper  lubrication  of 
gears  and  bearings. 

In  high  gear  the  transmission  shaft  is  locked  together  and  turns 


Fig.  80.     Reo  Transmission  and  Universals. 


as  one  solid  shaft.  This  arrangement  allows  the  power  to  flow  from 
the  engine  to  the  propellor  shaft  turn  for  turn  or  a  1  to  1  ratio. 
The  entire  gear  reduction  in  high  gear,  between  the  engine  and  the 
rear  road  wheels,  takes  place  in  the  ring  and  pinion  gear  ratio  in  the 


Clutches,  Transmissions,  Universals  •       75 

rear  axle.     This  varies  somewhat,  but  about  4  to  1  may  be  considered 
an  average. 

When  the  control  lever  or  gear  shift  lever  is  put  into  intermediate, 
neutral,  low,  or  reverse,  the  transmission  shaft  is  broken  or  divided 
into  two  independent  parts.  One  end  may  turn  at  speeds  different 
from  the  speed  of  the  other  end.  This  is  possible  since  the  shaft  is 
made  with  a  joint  and  bearing  at  a  certain  point  which  permits  of  the 


Pig.   81.     Packard    Passenger   Car   Clutch   and    Transmission. 

shaft  ends  turning  at  diflferent  speeds  except  when  on  high  gear. 
When  in  the  second  speed  position  the  line  of  flow  of  power  is  inter- 
rupted and  shunted  out  of  a  straight  line  through  the  idler  gear,  to 
the  counter  shaft,  thence  back  to  the  transmission  shaft,  through  the 
intermediate  or  second  speed  gear,  and  thence  on  to  the  propeller 
shaft  and  rear  axle.  This  allow^s  the  power  to  be  transmitted  to  the 
propeller  shaft  at  a  somewhat  reduced  speed,  the  exact  reduction  vary- 
ing but  being  approximately  5  to  3.  In  this  case  then  the  engine  to 
rear  wheel  reduction  would  be  about  1  to  7.  Shifting  the  control 
lever  to  low  or  first  speed  position  gives  a  further  reduction  through 
the  same  shunt  excepting  that  power  now  flows  from  the  engine  to 


76 


Automotive  Trade  Training 


the  transmission  shaft,  to  the  counter  shaft,  to  the  low  speed  gear, 
to  the  transmission  shaft  and  the  propeller  shaft.  This  gives  a  gear 
reduction  from  the  engine  to  the  propeller  shaft  of  approximately  3 
to  1,  with  a  consequent  gear  reduction  from  the  engine  to  the  road 
wheel  of  approximately  12  to  1.  No  set  figures  even  for  passenger 
cars  can  be  given,  as  reverse  or  low  may  be  as  low  as  20  to  1.  Speed 
ratios  from  that  figure  up  to  3  to  1  on  high  gear  may  be  found. 


Fig.   S2.     Packard 'Truck   Transaiission. 

Reverse  Gear. — When  the  corL|rol  lever  is  shifted  into  reverse 
position  the  sliding  gear  on  the  transmission  shaft  is  meshed  not 
with  a  gear  on  the  counter  shaft,  but!* -with  an  idler  gear  driven  by  the 
countershaft.  The  introduction  of  the  additional  gear  gives  the 
reverse  direction  of  drive.  The  line  of  flow  of  power  is  from  the 
engine  to  the  transmission  shaft,  to  the  counter  shaft,  to  the  idler 
gear,  to  the  reverse  gear,  to  the  transmission  shaft,  to  the  propeller 
shaft,  rear  axle  and  wheels. 

Special  Transmission  Types. — Transmission  gears  and  cases  are 
built  to  carry  varying  loads.  Trucks  and  tractors  require  heavier 
gears  and  cases.  To  obviate  the  danger  of  stripping  gears  in  shifting, 
some  trucks  are  Equipped  with  transmissions  in  which  the  teeth  of  the 
gears  are  always  in  mesh.  Speed  changes  are  effected  by  means  of 
sliding  dogs  which  engage  in  dog  clutches.  The  dogs  having  heavy 
jaws  are  less  likely  to  be  chipped,  bent,  or  broken. 


Clutches,  Transmissions,  Universals 


77 


Transmission  Troubles. — Transmission  troubles  most  apt  to  occur 
are  worn  or  broken  teeth,  worn  or  broken  bearings  and  worn,  bent,  or 
broken  shafts.  A  common  fault  which  causes  much  inconvenience 
is  to  have  the  gear  teeth  worn  a  little  tapering  or  sprung  out  of  line 
due  to  having  the  load  put  on  the  teeth  before  they  are  fully  meshed. 
This  condition  will  cause  the  gears  to  pop  out  of  mesh  on  a  long 
hard  pull.  If  taken  when  the  trouble  is  first  noticed  it  may  be 
remedied   by   putting  more  pressure   on   the   shift   rod  pawl   spring. 


Fig.   S3.    Pierce   Arrow   Progressive   Selective   Transmission. 
Note    the    improved    feature    as    shown    in    the    over-running    clutch    which    permits    of 
shifting  from   high  into  second   at  high  car  speeds. 


It  is  seldom,  however,  that  a  permanent  repair  is  effected  in  this 
manner.  For  a  permanent  repair  it  is  necessary  to  replace  the  worn 
gears  and  parts  with  new  ones. 

Planetary  Type  Transmission. — Here  is  used  a  mechanical  prin- 
ciple rather  difficult  to  grasp.  Instead  of  a  chain  of  gears  as  used  in 
the  selective  type  transmission  where  speeds  are  secured  by  shifting 
sHding  gears,  the  planetary  type  uses  a  set  of  gears  mounted  on  the 
flywheel  which  are  always  in  mesh.  In  the  case  of  the  Ford  car  three 
stub  shafts,  studs  or  pinions,  are  mounted  on  the  flywheel.  The 
triple  gears  are  mounted  on  these.  A  transmission  shaft  is  mounted 
on  the  center  of  the  flywheel.  On  this  shaft  is  mounted  a  set  of 
drums  and  three  spur  gears  of  varying  sizes  suitable  to  just  mesh 
with  the  three  sizes  of  the  triple  gears  and  the  spaces  between  their 
inner  edges  around  the  transmission  shaft. 


78 


AuTOMOTU'E  Trade  Tr 


\1N1NG 


High  Speed.  —  Just  as  in 
other  types  the  drive  is  straight 
through  the  transmission  on 
high  gear  to  the  universal  and 
propeller  shaft.  All  drums  and 
triple  gears  turn  as  one  mass 
and  part  of  the  flywheel.  On 
high  gear  the  triple  gears  are 
stationary  on  their  pinions, 
merely  taking  a  free  ride  on  the 
fly-wheel  as  it  turns. 

Slow  Speed.  —  Pressing  on 
the  slow  speed  pedal  stops  the 
slow  speed  drum  from  turning. 
When  it  is  stationary  and  the 
flywheel  is  turning,  the  triple 
gears  are  caused  to  turn  on  their 
pivots.  This  is  because  the  slow 
speed  drum  shaft  has  a  gear 
on  the  end  of  it  which  is  in 
mesh  with  the  triple  gears  on 
their  center  or  largest  part. 
As  these  triple  gears  revolve 
they  in  turn  drive  the  driven 
gear  which  is  mounted  on  the 
hollow  shaft  attached  to  the 
brake  drum  and  driving  plate. 
Their  driving  action  is  such  that 
they  cause  the  driven  gear  and 
parts  to  be  driven  backward 
Avhile  the  flywheel  turns  for- 
ward. While  the  flywheel  turns 
forward  three  revolutions,  the 
driven  gear  and  driving  plate  are 
backing  up  two  revolutions.  The 
driven  gear  being  mounted  on 
the  flywheel  has  turned  for- 
ward, however,  one  full  turn 
over  its  original  position.  (These 
figures  are  only  approximate.) 
Reverse. — The  same  princi- 
Fifr.  84.  Packard  Truck  showing  position  of  P^^  applies  here,  as  it  must  be 
Transmission  Units.  Understood     there     can     be     no 

change   of   direction   of   drive   from   the   triple   gears   since   they   are 
riveted  together  and  turn  as  one  at  all  times,  and  always  in  the  same 


Clutches,  Transmissions,  Univ^ersals  'J'^ 

direction.  These  gears  turn  in  the  same  direction  on  their  pivots  as 
the  flywheel  and  crankshaft  turn  on  the  engine  bearings.  In  both 
cases  the  direction  of  rotation  as  viewed  from  the  rear  is  counter 
clock-wise. 

Pressing  on  the  reverse  pedal  causes  the  reverse  drum  to  be  held 
while  the  triple  gears  travel  around  it.  Since  this  gear  doing  the 
holding  is  larger  than  that  part  of  the  triple  gear  engaging  it,  each 
turn  of  the  flywheel  will  give  more  than  one  turn  of  the  triple  gear. 
Four  revolutions  of  the  flywheel  will  give  five  turns  of  the  triple  gear 
which  drives  the  driven  gear  backward  at  the  same  rate  since  these 
gears  are  of  one  size.  In  the  case  of  reverse  gear,  while  the  flywheel 
travels  forward  four  revolutions,  the  driven  gear,  driving  plate  and 
brake  drum  are  driven  backward  five  revolutions.  This  is  one  more 
backward  for  the  propeller  shaft  then  the  flywheel  gave  forward. 
This  gives  a  reverse  gear  ratio  of  approximately  4  to  1.  This  reduc- 
tion is  in  the  transmission.  When  considered  in  relation  to  the  rear 
axle  ratio  of  about  4  to  1  the  gear  ratio  between  engine  and  rear 
road  wheel  is  about  16  to  1  on  reverse.  On  low  speed  the  ratio  is 
about  II  to  I,  on  high  speed  about  4  to  1.  (All  figures  given  approxi- 
mate.) 

Planetary  Principle  Explained. — The  term  itself  is  derived  from 
a  fancied  or  real  resemblance  to  the  action  of  the  planets  as  they 
travel  around  the  sun.  They  have  two  motions,  one  as  they  travel 
in  their  orbits  around  the  sun,  the  other  a  revolving  motion  as  the 
earth  turning  on  its  axis.  Since  the  principle  is  one  of  the  most 
puzzling  mechanical  principles  the  student  comes  in  contact  with, 
several  statements  of  problems  are  given. 

Suppose  you  are  aboard  a  railroad  train  one  mile  long.  We  will 
say  you  are  at  the  front  end  which  is  at  the  depot.  There  are  90 
cars  in  the  train.  While  the  train  moves  ahead  one  mile  you  walk 
toward  the  rear.  At  the  end  of  the  mile  you  have  come  to  the  sixty- 
first  car  from  the  engine  or  head  of  the  train.  The  rear  end  of  the 
train  or  the  caboose  is  where  the  engine  started.  How  far  have  you 
actually  traveled  with  reference  to  the  point  at  which  you  boarded 
the  train  or  how  far  are  you  from  the  depot? 

Now  suppose  the  train  is  on  a  circular  track,  and  that  the  caboose 
is  in  front  of  the  engine,  an  endless  train  on  an  endless  track.  Repeat 
the  problem.  Again  at  the  end  of  a  mile  travel  for  the  train  or 
engine  you  are  60  cars  from  the  engine  and  30  cars  from  the  rear 
of  the  train,  but  now  you  can  continue  walking  back  while  the  train 
goes  forward.  Each  mile  run  by  the  train  finds  you  one-third  of  a 
mile  farther  from  the  depot.  When  the  engine  has  traveled  three 
miles  you  have  traveled  one  mile  from  your  starting  point  or  once 
around  the  track. 

Next  suppose  you  start  walking  back  as  the  engine  starts  for- 


80 


Automotive  Trade  Training 


ward,  and  that  you  walk  back  120  car  lengths  while  the  train  and 
engine  travel  forward  one  mile  which,  as  stated,  is  equal  to  90  car 
lengths.  How  far  from  the  depot,  or  your  starting  point,  would  you 
be  and  in  which  direction?     Continuing  this  problem,  while  the  train 


Flywheel 


Reverse  Drum  Bushing 
Slow  Speed  Drum  Bushing 
Clutch  Discs 
Clutch  Disc  Drum 

Clutch  Finger  Pin 

Clutch  Push  Ring 

Driving  Plate 

Clutch  Finger  Adj.  Screv\r 

Clutch  Finger 

Clutch  Spring 


Clutch  Spring  Support 

Slow  Speed  Gear^    W^^^^^I^^^^H^l^^^\  \  \  Vlutch  Shift 

Clutch  Disc  Drum  Key 

Reverse  Gear^  ^^^^Sl^^^^^^^^^K  X       W  \  \  Driven  Gear  Sleeve  Bushing 

Transmission  Shaft 

Brake  Drum 
Driving  Plate  Screw 

Slow  Speed  Drum 
Fig.   85.     Ford   Planetary   Transmission   showing   drums,   gears,   clutcli   and    other   parts. 

goes  forward  three  turns  or  miles  you  will  have  walked  back  four 
turns  or  miles,  having  actually  traveled  one  mile  from  the  depot,  and 
that  in  a  reverse  direction  to  the  direction  the  train  is  being  run. 

The  Ford  flywheel  may  be  said  to  be  the  train  of  cars.  The 
driven  gear  with  its  hollow  shaft,  brake  drum  and  driving  plate  may 
be  said  to  be  the  person. 

Slow  Speed. — On  slow  speed  the  triple  gears  are  made  to  drive 
the  driven  gear  and  plate  backward  two  turns  to  three  forward  of  the 
flywheel.  Actually  it  travels  one  turn  ahead  to  three  ahead  of  the 
flywheel. 

Reverse. — On  reverse  speed  the  triple  gears  are  made  to  drive  the 
driven  gear  backward  five  turns  to  four  turns  ahead  for  the  flywheel. 
Actually  it  now  gains  one  turn  backward  to  four  ahead  for  the  fly- 
wheel. 

High  Speed. — The  clutch  is  not  used  at  any  time  except  when 
coming  from  neutral  into  high.     On  low  and  reverse  the  transmission 


Clutches,  Transmissions,  Universals  81 

bands  serve  as  friction  clutches  to  apply  the  power  evenly.  The 
clutch  on  neutral  is  held  out  by  the  hand  lever.  When  left  in,  which 
should  be  done  with  care,  it  locks  the  transmission  shaft  to  the  driv- 
ing plate,  by  means  of  the  friction  plates,  the  action  being  identical 
to  that  of  any  other  disk  clutch.  The  main  difference  is  that  it  is 
not  used  for  low  or  reverse  speeds. 

JOB  35.     REMOVING  TRANSMISSION  BANDS. 

1.  Take  off  the  door  on  top  of  the  transmission  cover. 

2.  Turn  the  reverse  adjustment  nut  to  the  end  of  the  pedal  shafts  (same 
for  the  brake  adjustment  nut),  then  remove  the  slow  speed  adjusting  screw. 

3.  Remove  the  bolts  holding  the  transmission  cover  to  the  crank  case  and' 
lift  off  the  cover  assembly. 

4.  Slip  the  band  nearest  the  flywheel  over  the  first  of  the  triple  gears,  then 
turn  the  band  around  so  that  the  opening  is  downward.^ 

5.  The  band  can  now  be  removed  by  lifting  it  upward, 

6.  The  operation  is  more  easily  accomplished  if  the  three  sets  of  triple 
gears  are  so  placed  that  one  is  about  ten  degrees  to  the  right  of  the  center  at 
the  top. 

7..     Each  band  is  removed  by  the  same  operation. 

8.  By  reversing  this  operation  the  bands  may  be  installed. 

9.  After  being  placed  in  their  upright  position  on  the  drums,  pass  a  cor<£ 
around  the  ears  of  the  three  bands,  holding  them  in  the  center  so  that  when 
putting  the  transmission  cover  in  place  no  trouble  will  be  experienced  in  getting 
the  pedal  shafts  to  rest  in  the  notches  in  the  band  ears. 

10.  The  clutch  release  ring  must  be  placed  in  the  rear  groove  of  the  clutch 
shaft. 

11.  With  the  cover  in  place  remove  the  cord  which  held  the  bands  in 
place  while  the  cover  was  being  installed. 

Caution.  Be  sure  no  small  parts  as  a  switch  key,  etc.,  are  left  where  they' 
may  fall  or  be  knocked  into  the  transmission  case;  also  tie  a  cord  to  all  smalt 
tools  being  used  to  prevent  loss. 

JOB  36.     RELINING  FORD  TRANSMISSION  BANDS. 

1.  Carefully  remove  the  old  lining. 

2.  True  up  the  metal  band. 

3.  Place  on  the  new  lining  and  clamp  it  fast. 

4.  Place  a  block  of  wood  in  the  vise,  end  grain  up,  shaped  to  conform  tot' 
inside  of  band. 

5.  Hook  the  band  over  this. 

6.  Drive  rivets  through  the  lining  into  the  wood.  Use  long  and  short 
rivets  as  required.  It  will  be  necessary  to  use  a  punch  on  some  of  the  rivets  to 
drive  to  the  seat. 

7.  Spread  rivets  having  the  rivet  head  resting  securely  on  metal.  With  a 
ball  pein  hammer  drive  the  ends  of  the  rivets  a  little  below  the  surface  of  the 
lining.  Unless  extrerhe  care  is  used  the  band  will  be  driven  out  of  true  and, 
require  more  time  to  straighten  than  the  entire  job  should  require. 

JOB  37.     ADJUSTING  CLUTCH  ON  THE  FORD  CAR. 

1.  Remove  the  plate  on  the  transmission  cover  under  the  boards  at  the 
driver's  feet. 

2.  Take  out  the  cotter  key  on  the  first  clutch  finger  and  give  the  set  screw 
one-half  to  one  complete  turn  to  the  right  with  a  screw  driver. 


82 


AuTOMoTivi-:  Tradi-:  Training 


«5      w     fe      Z   1 

Oto-c2       O     o£.    ea  on   *^.ta 


3.  Do  the  same  to  the  other  finger  set  screws. 

4.  Be   sure   to   give  each  the   same   number  of  turns  and   don't  forget  to 
replace  the  cotter  key. 

5.  After  a  considerable  period  of  service  the  wear  in  the  clutch  may  be 


Clutches,  Transmissions,  Universals  83 

taken  up  by  installing  another  pair  of  clutch  discs  rather  than  by  turning  the 
adjusting  screws  in  too  far. 

Caution:  Let  us  warn  you  against  placing  any  small  tools  or  objects 
over  or  in  the  transmission  case  without  a  good  wire  or  cord  attached  to  them. 
It  is  almost  impossible  to  recover  them  without  taking  off  the   transmission 


cover. 

JOB  38.     OVERHAULING  FORD  TRANSMISSION. 

1.  Remove  the  engine.     Job  56,  Chapter  7. 

2.  Remove  the  transmission  cover. 

3.  Remove  the  engine  block  with  the  transmission  assembly. 

4.  Remove  the  bands. 

5.  Release  the  clutch  finger  adjusting  pins. 

6.  Remove  the  driving  plate  studs. 

7.  Remove   the   clutch   discs.     Keep  in  order.     Replace  in  exact  former 
position. 

8.  Remove  the  disc  drum  stud. 

9.  Remove  the  disc  drum  with  a  special  drum  puller. 
10.     Pull  the  transmission. 

n.  Remove  the  driven  gear  from  the  back  end  of  the  brake  drum  using  a 
press  or  special  puller.     Be  careful  not  to  break  the  drum. 

12.  Drums  may  now  be  taken  apart  after  making  certain  that  woodruff 
Ivcys  are  removed  from  the  brake  drum  shaft. 

13.  To  renew  clutch  spring  and  collar:  (a)  Press  the  clutch  spring 
support  into  the  driving  plate  until  the  pin  is  exposed  or  in  line  with  holes;  (b) 
drive  out  the  pin;     (c)     release  the  tension  and  the  parts  may  be  disassembled. 

14.  Examine  triple  gear  rivets.     Replace  or  tighten. 

15.  Inspect  all  bushings  for  wear  and  replace  where  needed. 

16.  Any  necessary  magneto  work  may  be  done  at  this  time. 

17.  Clean  all  parts,  especially  clutch  discs.  Do  not  confuse  these.  Scrape 
with  knife  and  scrub  with  kerosene. 

18.  Repairs  having  been  made,  parts  may  be  reassembled,  reversing 
operations. 

JOB    39.     STANDARD    SELECTIVE    TYPE    TRANSMISSION 

OVERHAUL 

It  is  not  unusual  for  the  transmission  gears  to  be  so  worn  as  to  make  their 
replacement  necessary.  The  main  cause  of  this  is  the  failure  of  the  driver  to 
understand  the  proper  method  of  handling'  his  car  with  reference  to  speed 
•changes  and  clutch  manipulation.  Clashing  and  scraping  of  gears  in  shifting 
and  allowing  the  load  to  come  onto  them  when  only  partly  in  mesh  will  quickly 
•damage  the  gears.  The  transmission  shaft  also  is  subject  to  unusual  wear  for 
the  same  reasons.     In  overhauling  the  transmission  proceed  as  follows: 

1.  Inspect  the  job  to  see  what  is  necessary  to  remove  the  transmission 
case  as  a  unit.  In  many  cases  it  is  necessary  to  remove  the  rear  axle.  In 
others  this  is  not  necessary. 

2.  Take  the  case  to  the  bench  where  the  exterior  is  first  cleaned. 

3.  Inspect  the  case  to  learn  what  is  necessary  to  remove  the  bearings, 
shafts,  and  gear  assemblies.     Drain  the  oil. 

4.  Remove  the  gears  and  shafts. 

5.  Clean  all  parts  free  from  grease  and  oil. 

6.  Inspect  parts  to  see  which  must  be  replaced.  Where  gears  are  chipped, 
cracked,  or  worn  beveled,  it  is  necessary  to  replace  them.  Where  the  bearings 
and  bushings  are  worn  it  is  necessary  to  replace  them.     Inspect  the  bushings 


84 


Automotive  Trade  Training 


in  the  end  of  the  clutch  shaft  or  in  the  forward  end  of  the  transmission  shafts 
This  is  particularly  subject  to  wear, 

7.  Where  gears  are  riveted  together  or  onto  the  shaft,  it  will  be  necessary 
to  cut  out  the  old  rivets  and  replace  them  with  new  when  the  new  gears  are  in 
position. 

8.  Note  particularly  the  assembly  so  as  to  avoid  any  mistakes  in  reassem- 
bling the  parts. 


Clutches.  Transmissions,  Univeksals  85 

9.  When  the  gears  are  all  reassembled  in  the  case,  they  should  be  shifted 
to  see  that  the  full  width  of  the  teeth  is  engaged  when  they  are  in  mesh.  This 
is  very  important. 

10.  It  is  sometimes  possible  to  change  the  position  of  the  gears  by 
adjustments  on  the  shifting  forks. 

11.  See  that  the  pawls  and  springs  which  lock  the  shifting  fork  rods  in 
position  are  in  good  condition. 

12.  Where  the  clutch  is  a  unit  with  the  transmission  go  over  it  carefully. 
If  the  lining  is  dirty  and  greasy  it  should  be  cleaned  with  gasoline  or  kerosene. 
If  badly  worn  it  is  economical  to  replace  it  at  this  time. 

13.  Replace  the  overhauled  case  in  the  car,  making  certain  that  all  of  the 
bolts  and  nuts  are  properly  secured. 

14.  Fill  to  the  level  of  the  center  of  the  counter  shaft  with  the  proper 
lubricant.     (Job  40.) 

15.  Test. 

JOB  40.     STANDARD  SELECTIVE  TYPE  TRANSMISSION  CARE. 

1.  In  the  case  of  a  new  car  it  is  well  to  drain  away  all  old  oil  and  flush  out 
the  transmission  case  after  several  hundreds  of  miles  of  service.  The  reason 
for  this  is  the  fact  that  at  times  in  process  of  manufacture  foreign  substances 
are  left  in  the  transmission  case  and  may  work  considerable  damage.  Also, 
the  first  few  weeks  of  service  will  occasion  more  wear  as  the  parts  wear  in. 
than  the  succeeding  thousands  of  miles  will  produce.  All  filings,  chips  and 
fragments  of  metal  are  carried  by  the  oil  to  the  bearings,  unless  the  trans- 
mission is  flushed  and  drained  as  suggested. 

2.  Refill  the  case  with  the  oil  recommended  by  the  manufacturer.  This 
is  usually  a  heavy  black  molasses-like  oil  known  variously  as  transmission  oil, 
steam  cylinder  oil,  and  600  W.  In  some  instances  a  light  graphite  grease  is 
used,  and  in  other  cases  cup  grease  and  gas  engine  cylinder  oil  are  mixed  to 
form  a  "dope"  which  is  used  for  transmissions  and  rear  axles. 

3.  Never  fill  ^  transmission  case  with  a  cup  grease  alone.  It  will  all  work 
out  of  the  gears  and  bearings,  clinging  to  the  sides  of  the  case  where  it  does 
no  good  whatever. 

4.  After  the  first  proper  cleaning  the  case  should  be  drained,  flushed  and 
properly  refilled  each  5,000  miles. 

5.  If  the  shift  lever  tends  to  pop  out  or  jump  out  of  second,  or  any  other 
speed  on  a  long,  hard  pull,  it  is  likely  that  the  gears  are  a  bit  worn  or  l)eveled. 
This  trouble  is  sometimes  due  to  the  fact  that  the  shift  lever  pawl  spring 
needs  strengthening.  To  do  this,  remove  the  old  and  replace  with  a  new 
spring.     A  washer  under  the  old  spring  will  at  times  remedy  the  trouble. 

CLUTCHES 

The  use  of  the  clutch  might  be  said  to  be  similar  to  the  hitching 
up  and  unhitching  of  a  horse  from  a  wagon.  When  the  clutch  is  in, 
the  power  may  be  applied  to  move  the  load.  When  the  clutch  is  out, 
power  is  no  longer  being  transmitted  through  to  the  rear  axle.  Even 
and  smooth  application  of  power  is  possible  when  the  clutch  is  in 
good  condition  and  is  eased  in  by  the  driver.  A  sudden  leaving  in  of 
the  clutch  is  like  a  horse  starting  too  suddenly.  Disaster  is  likely  to 
be  the  result.  In  the  case  of  the  horse  and  wagon  sudden  starting 
results  in  broken  harness  and  singletrees.  The  same  equipment  will 
move  equal  and  larger  loads  for  many  years  if  the  horse  can  be 


86 


A  U  TO  M  OT 1 V E    1' K ADE    T R A 1 N  1  N  G 


taught  to  take  hold  on  the  load  slowly  and  steadily.  The  horse  will 
also  last  longer.  With  the  motor  car  sudden  dropping  in  of  the 
clutch  will  spin  the  wheels,  cut  tires,  stall  motors,  break  transmission 


Fig.   88.     Heavy    Duty    Clutch   of   the   Multiple   Disc    Typa. 

shafts  and  gears,  break  rear  axle  gears  and  shafts,  and  generally  bring 
rack  and  ruin  to  all  power  transmission  parts. 

An  even  steady  application  of  power  through  easing  in  of  the 
clutch  will  result  in  a  saving  of  all  parts  used  in  the  transmission  of 
power  as  well  as  tires.  Careful  handling  of  the  clutch  will  do  more 
than  any  one  other  thing  the  driver  is  tble  to  do  to  prolong  the  life 


Fiyvviu-el 


Fig.  89.    Marmon  Cone  Clutcb  and  Fly  Wheel. 


Clutches,  Transmissions,  UxNixeksals 


87 


of  the  car.  Careless  handling  of  the  clutch  in  the  shifting  of  gears 
and  general  use  of  it  will  take  many  years  from  the  normal  life  of 
the  chassis. 

Types  of  Clutches. — Plate,  multiple  disk  and  cone  clutches  are 
those  in  general  use.  These  may  be  designed  to  operate  with  or 
without  oil.  If  without,  they  are  said  to  be  dry  clutches,  if  running 
in  a  bath  of  oil  they  are  said  to  be  wet  clutches.     The  dry  clutch 


Fig.  90.    Allen  Transmission  and  Plate  Clutch 


holds  a  larger  degree  of  favor.  In  every  clutch  the  principle  of  opera- 
tion is  to  bring  some  material  possessing  great  friction  qualities  into 
contact  with  a  polished  steel  surface.  Pressure  of  the  clutch  springs 
holds  it  against  the  steel  surface  and  pressure  on  the  clutch  pedal 
leleases  this  first  pressure  by  compressing  the  clutch  springs.  The 
great  pressure  induced  in  the  clutch  spring  when  it  is  compressed  by 
the  clutch  pedal  and  related  parts  will  immediately  throw  the  clutch 
back  in  when  the  foot  pedal  is  released.  Because  of  the  strength  of 
the  clutch  spring  it  is  sometimes  impossible  to  leave  the  clutch  in 


S8 


Automotive  Trade  Training 


without  having  it  grab.  It  also  makes  it  very  hard  to  teach  the 
Device  how  to  handle  the  clutch  as  he  is  apt  to  think  that  all  he  needs 
to  do  is  to  release  all  pressure  from  the  pedal  to  have  it  engage 
properly.  Releasing  or  throwing  out  the  clutch  stores  in  the  clutch 
spring  the  power  used  in  throwing  the  clutch  in.  This  power  must 
-be  released  very  gradually  in  order  to  insure  proper  starting  of  the  car. 
Cone  Clutches. — The  cone  clutch  is  usually  fitted  into  the  rim  of 
the  flywheel.  The  flywheel  has  the  rim  turned  or  bored  out  on  a 
slight  angle  as  may  be  noted  in  the  illustrations.    This  insures  a  wedg- 


^^^^^^^^|RS^^__^  1       L -Sj 

^■■^^  ^^2>^  ■irr- •^*^'^^  ^  ^  ^ 

ill 

■n 

■H  ^  i^B^^^^^^         fci 

Fijr.   01.     Pan)   Pnssenyer   Car   Multiple   Disk   Chitch. 


ing  action  as  the  clutch  comes  in,  and  a  clearing  action  as  the  clutch 
is  thrown  out.  The  clutch  is  controlled  by  means  of  the  left  foot 
pedal  as  are  all  other  types.  The  spring  action  here  may  be  of 
several  types.  Either  one  large  spring  is  mounted  over  the  clutch 
i)haft,  or  the  clutch  shaft  is  provided  with  a  collar  and  web  through 
Avhich  bolts  are  run  allowing  three  or  more  springs  to  be  used  on 
the  back  of  the  flywheel  to  give  the  proper  tension  for  holding  the 
clutch  in  or  properly  engaged.  Either  style  may  or  may  not  be  ad- 
justable for  spring  tension. 

Plate  Clutch. — The  plate  clutch,  of  which  the  Borg  and  Beck  is 
the  most  popular  type,  is  one  in  which  a  single  plate  or  heavy  disk 


Clutches,  Transmissions,  Universals 


89 


is  gripped  between  two  rings  of  friction  material.  One  of  these 
rings  is  fastened  to  the  face  of  the  flywheel,  and  the  other  to  a 
thrust    ring   mounted   on   and   driven   by   the   flywheel.     When   the 


clutch  is  out,  the  single  driving  plate  is  left  free  to  stand  still  beween 
these  two  friction  lined  surfaces.  The  load  is  taken  by  this  plate  as 
the  clutch  is  left  in,  and  the  speed  of  the  plate  is  gradually  picked  up 
or  brought  up  to  a  speed  corresponding  to  that  of  the  engine  fly- 


90 


Automotive  Trade  Training 


wheel.  At  this  point  it  is  gripped  and  held.  Through  it  the  power 
then  flows  or  is  transmitted  to  the  transmission  propellor  shaft  and 
rear  axle. 

Disk  Clutches. — The  main  point  of  difference  in  the  wet  and  dry 
disk  clutch  may  be  said  to  be  one  of  operation.  With  the  dry 
clutch  the  driver  must  be  depended  on  to  leave  the  clutch  in  gradual- 
ly and  easily.  With  the  wet  clutch  the  oil  may  be  said  to  make  the 
operation  semi-automatic,  as  oil  left  between  the  plates  is  forced  out 
gradually,  until  when  the  oil  is  practically  all  forced  from  between 
the  plates  or  disks  the  clutch  is  holding  fully. 

The  manner  of  transmitting  the  power  is  identical  in  each  case. 
In  most  designs  a  set  of  pins  is  mounted  on  the  flywheel  and  on 
these  pins  is  mounted  one  set  of  disks.  When  the  flywheel  is  turning 
the  plates  mounted  on  it  turn  with  it,  although  they  are  free  to  move 
back  and  forth  on  the  pins  as  the  clutch  is  thrown  or  left  in.  These- 
disks  do  not  touch  the  clutch  shaft  but  have  an  opening  at  the  center 
large  enough  to  clear  it  readily.  When  disks  are  mounted  on  the 
clutch  shaft,  which  is  usually  the  front  half  of  the  transmission  shaft, 
they  are  made  and  mounted  in  such  manner  that  they  are  free  to  slide 
forth  and  back  on  the  shaft,  but  must  always  turn  with  it.  These 
disks  are  made  small  enough  to  permit  their  turning  inside  the  set 
of  pins  mounted  on  the  flywheel  and  carrying  the  other  set  of  disks. 
Of  the  two  sets  every  other  disk  is  mounted  on  the  flywheel  pins,, 
and  every  other  one  is  mounted  on  the  clutch  shaft. 

For  the  sake  of  clearness,  suppose  that  there  are  nine  disks  tO' 
the  clutch.  Five  of  these  would  be  mounted  on  the  flywheel  pins, 
and  it  is  likely  that  these  five 


would  carry  the  rings  of  fric- 
tion material.  Four  of  the 
disks  without  lining  would  be 
mounted  on  the  clutch  shaft, 
turning  only  with  it.  Pushing 
the  clutch  pedal  down  releases 
the  pressure  holding  the  plates 
or  disks  together,  thus  permit- 
ting them  to  separate.  With 
the  pressure  off,  the  disks  on 
the  clutch  shaft  gradually  come 
to  a  stop.  To  hasten  this 
action  most  designs  incorporate 
a  clutch  brake  which  comes  in- 
to action  as  the  clutch  pedal 
reaches  its  limit  of  travel. 
With  the  foot  pedal  down  and 
the   plates   separated,   the   clutch   is   said   to   be   out 


Fijr.  93.     Kelly   Springfield  Cone  Clutch. 


Releasing  the 


Clutches,  Transmissions,  Universals 


91 


clutch  pedal  permits  the  clutch  spring  to  throw  the  plates  back  to- 
gether at  which  position  the  clutch  is  said  to  be  in. 

As  stated  above,  the  set  of  plates  carried  by  the  flywheel  are  the 
usual  ones  to  receive  the  clutch  lining,  as  weight  is  not  detrimental 
in  this  case  as  it  is  in  the  case  of  the  set  on  the  clutch  shaft  which 
must  be  stopped  quickly. 


Fig.  94.     Borg  and   Beck   Dry   Plate   Clutch. 


Grease  and  Oil  Soaked  Clutches. — Occasionally,  especially  the 
exposed  cone  type  become  soaked  with  oil  and  grease,  and  slipping 
of  the  clutch  results.  This  surplus  oil  should  be  removed  and  the 
clutch  lining  treated  with  neatsfoot  oil. 

Neatsfoot  Oil. — This  is  the  standard  remedy  for  clutch  leathers 
and  linings.     Properly  used,   it  makes  the   leather  soft  and  pliable 


92  Automotive  Trade  Training 

bringing  out  its  natural  friction  qualities,  thus  giving  the  clutch  a 
chance  to  hold  onto  the  polished  steel.  Automotive  accessory  supply 
houses  carry  a  line  of  neatsfoot  oil  especially  prepared  for  clutch 
Hnings.  It  may  also  be  secured  from  drug  stores.  Castor  oil  is 
sometimes  used  as  a  substitute. 

Grabbing  Clutch. — This  condition  is  due  to  a  dry  hard  lining. 
Either  leather  or  fabricated  linings  are  subject.  An  application  of 
neatsfoot  oil  vv^ill  make  the  lining  soft  and  pliable,  after  which  it 
will  respond  to  careful  handling  by  the  driver  without  grabbing. 

Slipping  Clutch. — Just  the  opposite  of  grabbing  is  the  case  here. 
The  remedy  is  the  same.  The  lining  should  be  restored  to  its  original 
state  by  the  application  of  neatsfoot  oil.  At  times  the  wear  on  the 
lining  has  decreased  the  normal  spring  tension  or  the  springs  them- 
selves may  have  become  weak.  In  this  case  it  is  advisable  to  increase 
the  spring  tension,  or  to  replace  the  old  springs  with  new  ones. 
Sometimes  a  spring  will  become  broken.  This  fact  cannot  always 
be  detected  as  the  springs  are  frequently  entirely  enclosed.  To  in- 
spect the  spring  it  may  be  necessary  to  dismantle  the  clutch. 

Wet  Clutches. — A  clutch  made  to  run  or  to  operate; in  oil  may 
need  to  have  the  oil  drained,  the  parts  flushed  with  kerosene  and  the 
case  refilled  with  the  grade  of  oil  recommended  by  the  manufacturer 
of  the  car  in  question.  The  wet  clutches  may  be  of  any  type,  but 
the  wet  disk  is  most  popular.  The  wet  cone  clutch  is  also  in  use. 
If  the  oil  is  not  of  the  proper  consistency,  slipping  may  result. 

JOB  41.     CLEANING  AND  OILING  AN  EXPOSED  CONE  CLUTCH. 

In  cases  where  the  clutch  is  of  the  cone  type,  the  dirt  and  grease 
accumulating  on  it  will  result  in  clutch  trouble.  To  remove  it  the  floor  boards 
are  removed  and  a  stiff  paint  brush  and  kerosene  are  used  to  wash  the  oil  and 
dirt  away  from  the  parts.  When  the  exterior  parts  are  clean  the  brush  is  next 
cleaned  and  a  fresh  supply  of  kerosene  secured.  Prop  the  clutch  lever  with  a 
short  stick  to  hold  it  in  "out  position".  Wash  out  the  grease  from  the  clutch 
lining  and  the  face  or  seat  on  the  flywheel.     Apply  a  coat  of  neatsfoot  oil. 

JOB  42.     APPLYING  A  NEW  LINING  TO   A  CONE  TYPE   CLUTCH. 

When  the  clutch  facing,  which  is  usually  leather,  is  worn  or  burned  to  a 
point  where  it  will  no  longer  hold,  it  is  necessary  to  reline  or  recover  the  cone. 
Certain  fabrics  similar  to  brake  lining  are  also  used  for  clutch  facings.  The 
methods  of  replacing  old  with  new  are  similar  no  matter  which  material  is 
used.  It  is  a  very  excellent  plan  to  use  the  type  of  facing  recommended  by 
the  car  manufacturer  since  he  has  doubtless  experimented  with  a  number  of 
styles  and  knows  what  is  best  for  his  product. 

1.  In  most  cases  it  is  necessary  to  drop  the  transmission  unless  the  trans- 
mission happens  to  be  built  as  a  unit  with  the  rear  axle,  in  which  case  the  rear 
axle  may  have  to  be  pulled. 

2.  Make  such  further  arrangements  and  adjustments  as  are  necessary  to 
get  at  the  cone. 

3.  Remove  the  old  lining  being  careful  not  to  harm  the  cone  surface. 


Clutches,  Transmissions,  Univeksals 


93 


Clutch  Pedal 
should  be  ad- 
justed so  there 
is  %  inch  be- 
tween pe^al  and 
bottom  of  Toe 
Plate. 


This  Stop  is 
provided  for  the 
purpose  of  limit- 
ing the  amount 
of  throw,  so  that 
pedal  does  not 
hit   toe-plate. 


Adjust  here  in 
conjunction  with 
Clutch  Pedal 
Stop. 


I  f  sufficient 
/^throw-out  cannot 
be  obtained 
through  the  ad- 
justments, a  n 
earlier  separa- 
tion of  Clutch 
Discs  can  be 
obtained  by 
placing  a  #2  inch 
washer  on  each 
driving  stud  at 
this  point. 


Wear  of  Clutch 
during  first  500 
miles  moves 
Clutch  Collar 
away  from 
Clutch  necessi- 
tating freedom 
of  Clutch  Pedal 
so  it  can  move 
farther  up 
through  Toe 
Plate. 

Showing  Clutch 
fully  di  sen- 
gaged. 


Fig.   95.     Hudson    Clutch    Pedal   Throw   Out   Adjustment. 


94  Automotive  Trade  Train i 


Nc; 


4.  Fit  on  the  new  lining  stretching  it  evenly.  If  a  leather  cone  lining,  it 
is  well  to  soak  the  leather  in  water  or  neatsfoot  oil  before  applying. 

5.  Countersink  for  the  rivet  heads  and  see  that  they  are  sunk  well  under 
the  surface  of  the  lining. 

6.  In  cases  where  flywheel  disks  with  spring  arrangement  are  used,  they 
must  be  in  proper  position  when  the  facing  is  applied. 

7.  Reassemble  the  clutch,  being  very  careful  to  have  all  parts  cleaned. 
:greased  and  in  their  proper  position.  The  clutch  spring  may  be  compressed 
in  the  vise  and  wired  together  to  make  its  assembly  somewhat  easier. 

JOB  43.     RELINING  A  DISK  OR  PLATE  CLUTCH. 

When  the  take-up  on  this  type  of  clutch  is  all  used  so  that  the  clutch  can 
no  longer  be  adjusted  to  prevent  slipping,  it  is  necessary  to  remove  the 
transmission  and  clutch  in  order  to  dismantle  it  and  reline  the  disks  or  plates 
with  new  facings.     Use   the   style   recommended   by  the   manufacturer. 

1.  Remove  the  transmission  and  clutch  assembly,  or  such  parts  as  may  be 
necessary. 

2.  Dismantle  the  clutch  parts,  preserving  them  in  order. 

3.  Remove  the  old  lining. 

4.  Replace  the  old  with  the  new  lining»or  facings.  These  are  usually  applied 
two  to  one  disk  with  the  rivets  through  both.  In  selecting  rivets  for  this 
work  make  certain  that  they  are  just  the  proper  length  to  properly  head  up 
when  the  other,  or  head  end  of  the  rivet,  is  properly  countersunk  in  the  opposite 
Iming. 

5.  Set  the  countersunk  head  on  a  punch  held  in  the  vise  while  riveting 
the  end  over  with  a  small  ball  pein  hammer  and  rivet  set  or  punch. 

6.  Reassemble  clutch  using  extreme  care  to  have  all  parts  put  back  in 
order.     See  that  parts  are  clean  and  bearings  properly  adjusted  and  lubricated. 

7.  After  the  new  facings  are  in  service  a  short  time,  they  are  very  likely 
to  need  some  adjustment  for  the  first  wear  which  is  more  rapid  than  later 
when  they  have  been  worn  in. 

JOB  44.     ADJUSTING  A  BORG  AND  BECK  TYPE  CLUTCH. 

In  Figure  96  is  shown  the  Allen  car  with  indicated  clutcli  adjustment.  In 
some  cases  it  is  necessary  to  remove  the  inspection  plate  of  the  clutch  and 
flywheel  housing. 

1.  Remove  the  inspection  plate  if  such  is  used. 

2.  Turn  over  the  engine  until  the  two  adjusting  screws  are  located. 

3.  Holding  the  clutch  in  the  "out"  position  these  are  both  loosened. 

4.  Gently  tap  or  move  these  screws  in  a  clock-wise  direction  from  Y^"  to 
3/2".     Tighten  the  adjusting  screws.     A  very  little  movement  is  sufficient. 

5.  Replace  the  inspection  cover  and  floor  boards.  Test.  If  further 
adjustments  seem  necessary  make  them  in  accordance  with  the  above 
instructions. 

JOB  45.  CLUTCH  COLLAR  CARE. 

The  clutch  is  always  thrown  to  the  "out"  position  by  pressure  on  the  foot 
pedal.  This  pressure  is  transmitted  to  the  clutch  collar  and  through  to  the 
springs.  The  collar  is  standing  still  while  the  clutch  and  springs  are  revolving. 
A  tremenduous  pressure  is  thrown  onto  the  clutch  collar  bearing,  and  unless 
this  bearing  receives  proper  lubrication  the  collar  will  become  worn  and  make 
trouble  when  gears  are  to  be  shifted. 

1.  Keep  the  collar  lubricated  by  giving  the  grease  cup  a  turn  each  day 
when  the  car  is  in  service. 

2.  Make  certain  the  grease  reaches  the  collar  or  bearing. 


Clutches,  Transmissions,  Universals 


95 


3.  The  bearings  are  either  bronze  or  ball  thrust. 

4.  Do  not  allow  the  weight  of  the  foot  to  rest  on  the  clutch  pedal  while 
the  car  is  in  service  except  when  the  clutch  is  actually  in  service.     To  do  so 


Qutch  Pedal  Location  Adjustment 


Fig    9G.    Adjusting   Borg  and   Beck   Type   Clutch, 
is  likely  to  start  the  clutch  slipping,  or  by  placing  a  constant  strain  on  the  collar 
•cause  it  to  be  burned  out.     Either  of  the  above  conditions  is  serious. 

5.  A  burned  clutch  collar  acts  just  as  a  clutch  brake,  and  in  bad  cases 
•causes  the  clutch  to  stop  so  quickly  that  it  is  impossible  to  shift  gears  properly. 

UNIVERSAL  JOINTS 

Mechanical  Principle.— The  mechanical  principle  of  the  universal 
joint  is  simple,  although  in  its  application  some  very  complicated 
problems  are  met.  A  universal  joint  may  be  said  to  be  the  coupling 
of  two  shafts  endwise  so  that  the  one  may  give  a  rotary  motion  to 
the  other  when  forming  an  angle  to  it,  and  at  the  same  time  may  be 
moved  freely  in  all  directions.  Many  elaborate  and  complicated 
forms  have  been  worked  out  and  designed  to  fit  some  particular  need, 
but  all  forms  reduce  in  principle  to  the  plain  gimbal  joint  shown  in 
Fig.  100. 

To  a  casual  observer  the  need  for  universal  joints  in  the  propeller 
shaft  of  an  automobile  is  not  always  present.  At  first  glance  it  would 
seem  that  the  propeller  shaft  might  be  run  in  a  straight  line  from 
the  transmission  case  to  the  rear  axle  wnthout  the  use  of  any  uni- 
versal joints,  but  a  moment's  thought  will  show  how  impossible  this 
is.  The  absolute  necessity  for  a  universal  arises  from  the  fact  that 
the  engine  is  mounted  on  a  rigid  frame  and  therefore  moves  up  and 


96 


Automotive  Trade  Training 


iTEtRlNCr  VVUKEl, 


l-RONT 

UNIVEKSAL 

JOINT 


W./TOM'.1i.!( 


Fig.  97.     Front  end   of  Allen  Chassis. 

down  with  the  springs  while  the  rear  axle  follows  the  contour  of  the 
road.  Or,  the  result  may  be  said  to  be  the  same  as  if  the  frame  were 
still  and  the  rear  axle  moving  up  and  down'.  Aside  from  the  move- 
ments described  above  there  is  always  present  a  slight  weaving  of 
the  frame  which  adds  to  the  necessity  of  the  universal. 


FRHMT  PDripirt  I  f.fi  SHAFT  AND  UNIVERSAL  JOINTS 


SUPJOW 

0!L  TIGHT  WASHER 


REAR  PROPELLER  SHAFT  AND  UNIVERSAL  JOINTS 


Fig.  98.    Propeller   Shafts  and   Universal   .Joints   for   Trucli   Use. 
(Standardized  Military  Model  Class  B.) 


Clutches,  Transmissions,  Universals 


97 


In  some  machines  the  transmission  is  placed  at  a  distance  from 
the  clutch  and  is  not  attached  to  the  crank  case.  This  is  known  as 
mounting  the  transmission  admidship.  With  this  construction  it  is 
necessary  to  provide  universals  between  the  engine  and  transmission 
to  care  for  the  weaving  of  the  frame  and  the  likelihood  of  the  two- 
units  not  being  mounted  in  absolute  alignment. 


Fig.  99.     Illustrating  need  of  universals  and  contrasting  straight  line  and  angular  drive. 

Angle  of  Drive. — In  Fig.  99  is  shown  what  is  meant  by  straight 
line  and  angular  drive  as  applied  to  the  automobile  chassis.  The 
problems  which  must  be  solved  in  designing  a  universal  are  evident 
when  considering  the  lower  chassis.  In  the  ordinary  form  of  the 
metal  universal  the  ends  of  the  shaft  are  forked  and  fitted  over  a 
central  or  connecting  piece  in  the  shape  of  a  cross,  which  construction 
allows  each  shaft  to  be  moved  freely  in  any  direction.  The  amount  of 
movement  is  held  within  certain  limits.  A  rotary  motion  of  one  is 
readily  transmitted  to  the  other  without  much  loss  of  power  unless 
the  angle  of  drive  becomes  too  great.  It  is  evident  that  the  nearer 
to  a  straight  drive  the  less  the  friction  in  the  universals  and  the 
greater  efficiency  obtained.  The  nearest  approach  to  the  ideal  is  to 
have  the  motor  car  so  designed  that  the  line  of  drive  is  approximately 
straight  when  the  car  is  loaded.  Action  then  is  about  equal  above 
and  below  center  when  the  car  is  driven  over  the  road.  Cars  having 
a  considerable  angle  of  drive  when  under  full  load  have  that  angle 
greatly  increased  as  the  car  is  driven  over  rough  roads  and  spring: 
action  takes  place.     This  induces  faster  wear. 

Type  of  Universals. — All  universals  formerly  used  for  motor 
cars  were  made  from  metal.  These  were  either  the  ball  and  socket, 
block  and  trunion,  or  the  split  ring  types.     These  features  are  cared 


98 


AuTOMOTixi;  Trade  Tratninc, 


Fig.    100.     Simple   Metal   Type    of   Universal. 


for  in  every  case ;  that  is,  arrangement  is  made  within  certain  limits 
for  the  transmission  of  power  from  one  shaft  to  the  other  no  matter 
what  angle  the  shafts  may  .be  in  with  relation  to  each  other.  One 
other  provision  is  also  made.     That  is  the  slip  joint. 


Fig.  101.     Thermoid  Hard.v  Fabric  T^niversal  in  Detail  and  Assembly. 


Fig.   102.     Result   of  Thermoid   Hardy    Strength   Test. 

Slip  Joint. — When  the  rear  springs  are  in  action  the  distance 
between  the  transmission  and  the  rear  axle  is  constantly  changing. 
When  the  springs  are  compressed  and  when  they  rebound  the 
distance  is  first  shortened  and  then  lengthened.     Provision  for  tak- 


Clutches,  Transmissions,  Universals 


99 


ing  care  of  this  difference  is  made  within  the  universal  joint  in  what 
is  known  as  the  slip  joint.  Referring  to  Fig.  98  it  will  be  seen  how 
the  spliced  shaft  moves  back  and  forth  within  its  counterpart. 

Fabric  Universals. — The  Thermoid-Hardy  universal  is  perhaps 
the  foremost  one  of  this  type.  It  consists  of  a  coupling  in  which  the 
ends  of  the  shafts  are  permanently  bolted  to  disks  of  flexible  fabric 
in  such  manner  that  there  are  no  metal  to  metal  bearing  surfaces. 
Friction  is  thus  entirely  eliminated  and  no  lubrication  whatever  is 
needed.  The  result  is  a  pliable  joint  of  enormous  strength  and  great 
durability,  which  requires  no  protection  and  no  attention.  The  fabric 
is  so  treated  that  it  is  impervious  to  oil  and  water  and  no  amount  of 
sand  and  dirt  from  the  roadbed  can  injure  it.  The  elastic  disks  act 
as  cushions  in  the  driving  shaft,  absorbing  all  the  damaging  shocks 
•and  jolts  which  are  intensified  by  metal  to  metal  contact.  This' 
tends  to  increase  service  and  protects  the  other  parts  of  the  car  used 
in  transmission  of  power.  Another  great  advantage  is  the  absolute 
silence  of  the  joints  in  operation. 

The  shock  absorbing  properties  of  the  fabric  universal  are  espe- 
cially noticeable  in  starting  a  car.     The  engine  is  called  on  to  move 


Fig.  103.    Thermoid  Hardy  Universal  applied  to   the   rear  end  of  propeller  shaft 

for  a  truck. 

a  ton  or  more  of  dead  weight  each  time  the  clutch  is  left  in.  The 
flexible  fabric  is  so  elastic  that  the  engine  is  permitted  to  take  up  the 
load  without  a  sudden  clash  of  metal  parts,  as  the  forward  end  of  the 


100 


Automotive  Trade  Training 


propeller  shaft  is  permitted  to  turn  a  bit  before  causing  the  axle 
shafts  to  start  turning.  The  result  is  a  more  even  flow  of  power  from 
the  engine  to  the  drive  wheels  with  less  severe  strain  on  the  running 
gear.  The  elasticity  also  insures  an  even  turning  speed  as  an}) 
fluctuations  in  the  velocity  of  the  propeller  shaft  are  taken  up  and 
equalized  in  the  joint. 

Slip  Joint  Unnecessary. — One  advantage  of  the  flexible  fabric 
construction  for  a  universal  is  that  it  allows  considerable  longitudina 
or  end  play.  The  need  of  this  for  the  all  metal  joint  has  beer 
explained.  The  fabric  type  will  care  for  as  much  as  one  inch  play 
This  is  as  much  as  is  ever  found  in  any  well  designed  car  and  mon 
than  in  most  cases. 


TRANSMISSION 

Fill  with  Tranvfniuioft  frca** 
monthly  throggh  gcw  ■hiti 
• cpenin« 


UNIVERSAL  JOINX. 

Fill  w.th  leatpoonh 
ol  f  rraM  naenthly 


UNIVERSAL  JOINT    y^ 

Pill  with  icatpoonful  of  grc«s«.  monthly 

Fig.  104.    Universal  Joint  Lubrication.     Note  Leather  Boots. 


Clutches,  Transmissions,  Universals  101 

A  test  of  this  type  of  universal  was  made  to  learn  the  compara- 
tive strength.  A  picture  of  the  result  is  shown  in  Fig.  102.  As  can 
be  seen  the  tubular  shaft  was  twisted  before  the  joint  proper  was 
damaged  at  all. 

JOB  46.     UNIVERSAL  JOINT  LUBRICATION. 

Because  of  the  fact  that  it  will  operate  without  lubrication,  the  universal 
joint  is  perhaps  the  most  neglected  unit  on  the  car.  Lack  of  lubrication  is 
certain  to  cause  the  metallic  joint  to  deteriorate  very  rapidly  and  become  very 
noisy. 

1.  Raise  the  floor  boards. 

2.  Locate  and  remove  the  filler  plug.  This  is  usually  a  one-eighth  or  one- 
quarter  inch  pipe  plug. 

3.  With  a  grease  gun  force  into  the  plug  hole  a  quantity  of  medium  cup 
grease  sufhcient  to  fill  the  joint  about  one-half  full. 

4.  In  cases  where  the  joint  is  dry  due  to  neglect  of  proper  filling,  or  due 
to  replacement  of  parts  or  overhaul,  it  is  well  to  apply  a  quantity  of  medium 
oil  to  start  lubrication  and  then  fill  with  the  cup  grease. 

5.  Never  fill  the  joint  entirely. 

JOB  47.     UNIVERSAL  JOINT  OVERHAUL. 

In  all  cases  where  the  universal  has  worn  to  such  a  degree  that  there  is  an 
unwarranted  amount  of  backlash,  it  is  necessary  to  replace  the  parts  subject 
to  wear.  In  removing  the  universal  joint  it  is  frequently  necessary  to  pull 
the  rear  axle.  In  some  cases  where  two  universals  are  used  this  is  unnecessary. 
In  every  case  where  a  torque  tube  is  used  it  is  necessary  to  pull  the  axle. 

1.  Inspect  the  job  to  learn  what  work  is  necessary. 

2.  Do  this  preliminary  work  and  pull  the  universal. 

3.  Take  the  universal  to  the  bench  and  clean  free  of  all  grease  and  oil. 

4.  Dismantle  completely.     Inspect  and  order  the  parts  needed. 

5.  Reassemble  and  replace  in  the  car.  ^ 

6.  Lubricate  as  suggested  in  Job  46. 


CHAPTER  5 
POWER  GENERATION  AND  POWER  PLANTS 


ENGINES,  POWER  GENERATION 

Power  Generation. — In  order  that  the  student  may  properly 
understand  engine  care  and  operation,  and  more  especially  all  phases 
of  engine  repair  work,  he  must  have  a  thorough  working  and  speak- 
ing knowledge  of  the  theory  of  the  internal  combustion  engine.  He 
must  know  exactly  the  relation  of  moving  parts  to  each  other,  also 


Fig.  105.    Packard  Liberty  Airplane  Engine. 

the  closeness  and  types  of  fits  between  them.  He  must  know  the 
proper  functioning  or  working  of  each  and  every  part  of  the  engine, 
be  it  bolt  or  shaft,  gear  or  valve,  block  or  gasket,  port  or  piston. 
Knowing  this,  he  will  be  in  a  position  to  grasp  the  purpose  and 
meaning  of  the  various  systems  as  the  oiling  system,  the  fuel  system, 

102 


Power  Generation  and  Power  Plants 


103 


the  cooling  system,  the  ignition  system,  the  starting  and  lighting 
system,  all  of  which  are  built  in  as  an  integral  part  of  the  modern 
motor  car  engine  or  power  plant.  To  these  units  is  added  the  trans- 
mission to  make  what  is  termed  the  unit  power  plant. 


Pig.   106.     Continental   Engine  7R. 


Fig.  107.    Sectional  View,  Continental  7R. 


104 


Automotive  Trade  Training 


The  commercial  power  plant  is  a  plant  where  under  one  or  more 
roofs  is  housed  the  means  of  developing  or  generating  power  to  be 
transmitted  elsewhere  in  the  community,  there  to  light  lamps,  to 
turn  machines  and  to  do  work.  The  automobile  power  plant  is  that 
part  housed  under  the  hood  and  used  to  generate  power  which  trans- 
mitted to  the  rear  axle  will  propel  the  car.  Incidentally  it  also  gener- 
ates its  own  electrical  energy  which  is  used  to  ignite  the  charge  with- 
in the  cylinders,  light  the  lamps,  charge  the  storage  battery,  and  per- 
form other  minor  operations. 

Limitations  of  space  and  need  of  great  power  have  resulted  in 


Fig.  108.     Dodge  Power  Plant,   Left   Side. 

the  engineers  perfecting  the  design  of  the  various  units  in  a  remark- 
able manner,  until  nowhere  else  is  to  be  found  such  compactness  and 
flexibility  of  power  as  in  the  automotive  equipment  power  plants. 
The  basis  of  their  start  was,  of  course,  the  cylinder  in  which  a  charge- 
of  fuel  was  exploded  and  made  to  do  work.  It  is  common  knowledge 
that  when  certain  fuels  are  set  afire  they  burn  so  fast  that  the  result 
is  termed  an  explosion.  Natural  gas,  acetylene  gas,  alcohol,  gasoline, 
kerosene,  benzine,  nitro-glycerine,  and  certain  other  fuels  are 
regarded  by  all  as  being  dangerous  to  handle  due  to  their  Hability, 
tinder  certain  favorable  conditions,  to  explode.  Except  for  the  tre- 
mendous force  or  power  developed  by  these  when  exploded  no  one 
would  fear  them.  Coal  is  handled,  usually  without  a  thought  of 
danger  or  harm  from  an  explosion.  Yet,  it  is  quite  possible  to  pul- 
-verize  this  fuel,  mix  it  with  the  proper  amount  of  air  or  oxygen  and 
explode  it  with  disastrous  or  beneficial  results,  depending  altogether 


Power  Generation  and  Power  Plants  105 

on  whether  or  not  the  force  or  power  generated  from  the  explosion 
is  directed  into  the  proper  channels  by  means  of  some  mechanical 
device. 

In  the  case  of  the  internal  combustion  engine,  and  more  partic- 
ularly the  gasoline  engine  as  used  in  the  motor  car,  the  engineers  have 
designed  and  built  a  machine  which  takes  a  raw  fuel,  breaks  it  into 
small  particles,  mixes  the  vaporized  particles  with  air,  puts  a  quantity 
of  the  mixture  in  a  cylinder,  forces  that  quantity  into  a  small  space, 


Fig.   109.     Dodge   Power   Plant.    Right   Side. 

• 

sets  it  on  lire  thus  exploding  it,  uses  the  power  developed,  throws  off 
the  burned  or  useless  smoke  and  gases,  and  is  ready  and  able  to  do 
this  complete  operation  hundreds  of  times  a  minute.  As  this  chain 
of  events  takes  place  in  first  one  cylinder  and  then  in  another,  and 
in  regular  intervals  of  time  in  each  and  every  cylinder,  the  engine 
develops  that  regular  flow  of  power  which  is  so  desirable.  All 
systems  saving  only  the  lighting  serve  one  major  purpose  only,  that 
of  generating  power  and  delivering  it  to  the  transmission  system. 
Each  bit  of  fuel  burned  in  each  cylinder  means  a  bit  of  power 
developed  and  controlled  to  do  the  work  we  want  performed.  A 
certain  per  cent  of  the  power  developed  within  the  engine  is  neces- 
sarily used  to  overcome  internal  losses  as  friction,  etc.,  and  keep  the 
engine  itself  in  motion.  Only  the  surplus,  over  and  above  this 
amount,  is  available  for  driving  the  car. 

Names  and  Location  of  Engine  Parts. — Whether  the  engine  is  a 
four,  six,  eight,  or  twelve  cylinder,  the  general  design  is  quite  sim'lar. 


106 


Automotive  Trade  Training 


Parts  used  in  the  construction  bear  the  same  names  and  general  rela- 
tion to  each  other.  Referring  to  the  two  cuts  of  the  Dodge  Unit 
Power  Plant  and  the  cut  of  the  Dodge  Engine  Section  (Figs.  108, 
109,  110),  the  proper  names  of  most  engine  details  may  be  learned. 


Other  cuts  appearing  elsewhere  will  also  prove  of  help  to  the  student 
in  becoming  familiar  with  general  design  and  names  of  engine  parts. 
Operation. — Since  the  gasoline  engine  is  not  capable  of  generat- 
ing power  until  first  set  in  motion  from  an  outside  source  of  energy, 
an  electric  starting  motor  has  been  incorporated  in  most  cases.     Press- 


Power  Generation  and  Power  Plants 


107 


ing  the  starting  switch  draws  current  from  the  storage  battery,  which 
drives  the  starting  motor,  which  in  turn  drives  the  crankshaft,  or 
turns  it  over  with  all  the  parts  directly  related  to  it,  in  fact  all  the 
moving  parts  of  the  engine,  until  a  fuel  charge  has  been  drawn  in, 
compressed  and  fired.  When  this  first  chaige  is  fired  the  engine 
becomes  active,  having  now  power  within  itself  to  keep  the  parts 
turning.  However,  it  is  so  arranged  that  in  another  half  revolution, 
in  the  case  of  a  four,  another  charge  is  fired  in  another  cylinder,  in 
another  half  revolution  another  charge  is  fired  in  the  third  cylinder, 
in  still  another  half  revolution  the  fourth  and  last  cylinder  is  fired, 
and  after  still  another  half  revolution  of  the  crank  shaft  the  cylinder 
first  to  fire  is  fired  for  the  second  time.     Each  of  the  other  follows 


Fig.  111.     Packard   Twin   Six  Unit   Power  Plant. 

in  its  regular  turn,  thus  keeping  the  engine  operating  and  developing 
the  desired  power.  The  operation  of  the  engine  with  reference  to 
handling  fuel  is  called  the  four  cycle  principle,  more  properly  called 
the  four  stroke  cycle. 

The  Four  Stroke  Cycle. — A  cycle  is  a  completed  chain  of  events 
which  leaves  the  operation  finished  so  that  the  next  event  due  is  the 
one  with  which  the  start  was  made.  To  illustrate,  consider  the  cycle 
of  seasons.  The  year  which  is  one  cycle  of  seasons  is  completed 
every  365  days.  These  365  days  are  divided  into  twelve  months  while 
the  twelve  months  are  divided  into  four  seasons,  winter,  spring, 
summer,  and  fall.  Since  the  birth  of  Christ,  1921  of  the  cycles  of 
seasons  have  been  completed  and  the  1922nd  is  well  under  way.     The 


108 


Automotive  Trade  Training 


seasons  occur  in  order  always.  The  Creator  has  arranged  the 
mechanical  features  of  the  Universe  so  that  no  other  order  is  possible. 
The  earth  revolves  on  its  axis,  follows  on  its  way  on  its  orbit,  the 
sun  retains  its  position  and  as  a  result  we  regularly  have  winter, 
spring,  summer,  fall,  etc.,  etc.,  cycle  of  seasons  after  cycle  of  seasons. 
In  designing  the  gas  engine,  engineers  have  found  that  there  are 
four  events  or  operations  which  must  always  follow  each  other  with 
unvarying  regularity.  If  they  occur  in  any  other  manner  for  any 
reason,  the  engine  fails.  Practice  is  absolutely  dependent  on  prin- 
ciple. To  obtain  power  from  any  cylinder  of  any  engine  the  events 
for  that  cylinder  must  be  in  the  following  order :  Intake  of  air  and 
fuel,  compression  of  charge,  explosion  of  charge  and  development  of 
power,  exhausting  of  burned  gases  thus  completing  for  that  cyHnder 
the  first  cycle  of  operations.  However,  the  engine  does  not  stop  with 
the  completion  of  the  cycle  but  goes  immediately  into  another  cycle 
until  each  cylinder  has  a  continuous  chain  of  events  occurring  in  it, 
as  intake,  compression,  power,  exhaust;  intake,  compression,  power, 
exhaust;  and  on  and  on.      ^ 

The 'student  will  remember  that  while 
one  cylinder  is  running  its  cycles  the  others 
are  falling  in  line  with  theirs,  so  that  the 
events  occurring  in  each  cylinder  might  be 
compared  as  given  in  "Fig.  112,  representing 
the  order  in  the  Dodge  engine.  Also 
remember  that  a  cycle  requires  four  strokes 
of  the  piston,  and  two  revolutions  of  the 
crankshaft  and  flywheel  to  complete  it."  "sA 
stroke  of  piston  and  piston  rod  is  either  from 
top  to  bottom  or  from  the  bottom  of  the 
cylinder  to  the  top  of  it. 

One  stroke  equals 
cycle. 

Two  strokes  equal  1  revolution  or  J4 
cycle. 

Three  strokes  equal  1^  revolutions  or 
%  cycle. 

Four  strokes  equal  2  revolutions  or  1 
cycle. 

In  the  diagram  the  width  represents  the 
length  of  a  cycle.  Two  revolutions  make 
one  cycle.  Four  strokes  make  one  cycle. 
The  firing  order  of  the  cylinders  is  1-3-4-2. 
Supposing  cylinder  1  is  on  power,  cylinder 
3  must  be  on  compression  since  in  this  case 
it  fires  next.     Cylinder  4  must  be  on  intake 


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A  revolution  or  ^ 


Power  Gexeration  and  Power  Plants 


109 


<       O       eo 
-S—    •*>       3 


while  3  is  compressing,  and  on  comoression  while  3  is  firing.  Two, 
which  is  the  fourth  cylinder  to  fire,  must  be  on  exhaust  while  1  is 
firing,  because  it  will  be  on  intake  when  3  is  fired,  and  on  compres- 


110 


Automotive  Trade  Training 


sion  when  4  is  fired.  In  the  case  of  the  four  cyhnder  engine,  at  no 
time  is  the  same  event  occurring  in  two  or  more  cylinders  at  the 
same  time.  For  each  half  revolution  of  crank  shaft  and  flywheel 
one  is  fired,  one  exhausts  burned  gases,  one  draws  in  a  new  charge, 
and  the  other  compresses  a  fuel  charge.     There  are  always  as  many 


EXHAUST  VALVE 


EXHAUST    Ot/TLCT 
PASSAGE 


GAS    INTAKE 
PASSAGE 


EXHAUST   VALVe 


xmaust  outlet 

/     PASSAGE 


^XHAUST  VALVE 

EXHAUST  OUTLET 
/     PASSAGE 


GAS  INTAKE 
PASSAGE 


EXHAUST  VALVE 


EXHAUST  OUTLET 
PASSAGE 


Fig  114.    Four  Stroke  Cvcle  illustrated. 

cycles  in  operation  in  an  engine  as  that  engine  has  cylinders.  In 
c.  four  cylinder  engine  four  cycles  are  in  operation ;  in  a  six,  six 
cycles ;  in  an  eight,  eight  cycles ;  and  in  a  twelve,  twelve  cycles. 
Each  cycle  will  be  completed  in  two  revolutions  of  the  crankshaft. 
Since  in  the  case  of  the   four  cylinder  engine,   four   cycles   are  in 


Power  Generation  and  Power  Plants 


111 


112 


'  Automotive  Trade  Training 


operation  four  will  be  completed  in  two  revolutions  of  the  crank- 
shaft ;  in  the  six,  six  will  be  completed  in  two  revolutions ;  in 
the  eight,  eight  will  be  completed,  and  in  the  twelve,  twelve  will  be 
completed  in  the  two  revolutions.  One-half  the  number  of  cylinders 
represents  the  number  of  cycles  completed  each  revolution  of  the 
crankshaft,  and  since  there  is  one  power  impulse  for  each  cycle  com- 
pleted, one-half  the  number  of  cylinders  represents  the  number  of 
power  impulses  per  turn  of  the  flywheel  and  crankshaft.  This  gives 
two  power  impulses  per  revolution  of  engine  flywheel  for  a  four 
cylinder  engine,  three  for  a  six  cylinder,  four  for  an  eight,  and  six  for 
it  twelve  cylinder  engine.  From  this  is  easily  learned  the  reason  for 
the  more  even  flow  of  power  as  the  number  of  cylinders  is  increased. 
Cycles   Completed  per  Minute. — Since  the   above   figures   repre- 


Fig.    116.     Peerless    Eight    Power    Plant. 

sent  actual  conditions  v^ithin  the  four  cycle  engines,  and  1,000  revolu- 
tions per  minute  may  be  taken  as  an  average  engine  speed  in  driving, 
it  would  be  well  for  the  student  to  gain  an  idea  of  the  rapidity  with 
which  the  events  in  a  cycle  take  place,  and  what  it  has  meant  to 
design  an  engine  which  would  insure  their  occurring  in  right  order 
and  in  the  fraction  of  a  second.  In  a  four  cylinder  engine  there  are 
two  power  impulses,  meaning  two  completed  cycles  per  revolution, 
therefore  there  would  be  2,000  completed  cycles  within  the  engine 
per  minute.  Since  each  cycle  means  four  events  there  will  be  8,000 
events  within  the  engine  per  minute.     Two  thousand  of  these  are 


Power  Generation  and  Power  Plants  113 

intakes,  2,000  are  compressions,  2,000  are  power  impulses,  and  2,000 
are  exhaust  operations. 

In  a  twelve  cylinder  there  would  be  6,000  cycles  completed  per 
minute  which  means  24,000  events  or  operations,  which  include  6,000 
power  strokes,  6,000  exhaust  strokes,  6,000  intake  strokes,  and  6,000 
compression  strokes.  The  student  would  find  interest  in  estimating 
the  number  of  events  or  operations  within  the  six  and  eight  cyHnder 
engines,  and  then  the  number  occurring  in  a  twelve  cylinder  when 
driven  at  its  highest  rated  speed.  While  one  year  of  365  days  is. 
needed  to  complete  a  cycle  of  seasons,  as  many  as  1,700  cycles  may 
be  completed  within  a  single  cylinder  of  a  modern  engine  in  a  minute. 
Multiplying  this  by  the  number  of  cylinders  gives  a  rather  accurate 
figure  for  the  modern  high  speed  engine  at  its  best  or  greatest  speed. 
Each  one  of  these  cycles  requires  four  strokes  of  a  piston  to  com- 
plete it. 

How  it  has  been  possible  to  have  this  number  of  operations  occur 
in  such  short  spaces  of  time  will  be  learned  in  studying  the  function- 
ing of  engine  parts,  particularly  valves,  cams,  timing  gears,  pistons, 
camshafts,  and  crankshafts. 


CHAPTER  6 


FUNCTIONS  OF  ENGINE  PARTS 


TROUBLES  AND  REPAIRS 

Crank  Case. — The  crank  case  is  used  as  a  rule  to  carry  all  other 
parts  of  the  engine  and  is  in  turn  carried  by  brackets  cast  integral 
with  it  or  bolted  to  it.  The  outer  ends  of  these  brackets  are  attached 
to  the  frame.  If  there  are  three  of  these  brackets  supporting  the 
weight  of  the  engine,  the  engine  is  said  to  have  three  point  suspen- 
sion; if  four,  four  point  suspension.  The  three  point  suspension  is 
most  in  favor  as  it  permits  of  greater  movement  within  the  car  frame 
without  throwing  strains  onto  the  engine  itself.     The  crank  case  is 


Fig.  117.     standard  Eight  with  Pan  or  lower  half  of  crank  case  dropped.     Note  position 

of   Pistons.    Rods,   etc. 

•usually  divided  into  upper  and  lower  halves.  The  engine  brackets 
may  be  attached  to  either  part  but  are  found  more  often  on  the  upper 
half.  This  part  is  usually  the  one  carrying  the  main  engine  bearings. 
"When  this  arrangement  is  used,  the  upper  part  is  called  the  crank 
case  while  the  lower  part  is  called  the  oil  pan.  This  arrangement 
frees  the  oil  pan  of  all  weighty  parts  and  permits  of  the  pan  being 
dropped  for  bearing  inspection,  either  rod  or  main  bearings,  also  for 
cleaning,  without  removing  the  engine  from  the  frame  of  the  car- 
Fig.  119,  showing  the  Marmon  crankshaft  mounted  in  the  crank  case 
with  oil  pan  removed,  illustrates  this. 

While  the  above  is  the  most  approved  design,  engines  may  be 

114 


Functions  of  Engine  Parts 


115 


Fijr.   lis.     Sectional  View  of  Cadillac  Crank   Case. 

found  with  the  l:)rackets  on  the  lower  half,  and  even  in  rare  instances 
crankshaft  bearings  may  be  found  in  the  lower  half  of  the  crank  case. 
In  still  other  instances  the  crank  case  is  cast  in  one  piece  with  inspec- 
tion plates  on  the  sides  to  be  removed  for  minor  repairs.     This  is 


m 

*                • 

Au 

B 

m 

t 

=^ 

18$ 

fc,r*i»  !,5 m 

I 

'ik 

^ 

--x^l.> 

Fig-.  119.    Marmon  Upper  Half  Crank   Case. 

called  the  barrel  type  case.  For  major  repairs  the  engine  must  be 
lifted  from  the  frame  of  the  car.  Then  all  cylinder  blocks  must  be 
pulled  from  the  case  as  well  as  all  rods  and  pistons  removed  from  the 
crankshaft,  after  which  the  shaft  with  the  main  bearings  loosened  and 


116 


Automotive  Trade  Training 


ST  RAIN  en  sc/fcf^ 


Fig.  120.     Cole  Eight,   Oil  Pan  and   Tray. 

removed  may  be  pulled  from  the  end  of  the  case  through  the  opening 
left  when  the  main  bearings  were  removed.  It  is  also  well  to  remove 
the  flywheel  before  attempting  to  remove  the  shaft  as  there  is  less 
danger  of  harming  bearings  or  shaft  without  its  added  weight.  In 
the  case  of  some  eights  the  crank  case  is  split  vertically  and  the  shaft 
bearings  attached  to  one-half  of  it. 


Fig.  121.     Marmon  Cylinder  Blocks  with  Head   Removed. 

Owing  to  the  size  of  the  crank  case,  aluminum  has  been  used 
very  extensively  in  casting  them  since  it  materially  reduces  the 
weight.  However,  as  this  metal  is  always  costly,  an  increasingly 
large  number  of  the  oil  pans  are  made  from  pressed  steel.  In  some 
instances  the  upper  half  is  made  from  cast  iron  and  is  supported  with 
pressed  steel  brackets. 


Functions  of  Engine  Par 


rs 


117 


In  a  number  of  instances  the  upper  half  of  the  case  is  cast  inte- 
gral with  the  cylinder  casting,  and  in  some  instances  the  barrel  type 
case  is  cast  integral  with  the  cylinder  blocks.  Either  method  makes 
for  fewer  parts.  Each  has  its  own  peculiar  advantages  and  dis- 
advantages as  will  be  noted  in  study  and  shop  practice. 


Distributor 


intake  Clamp 


Crank  Shaft 


Cam 
Gear 


Bearing 
Stud 


Crank  Shaft    Cr;mk  Shaft 
Ct-ar  Bearing  Cap 


Fig.  122.     Front  View  Apperson  Eight,  L  Head  Motor. 

In  all  cases  the  lower  half  or  oil  pan  is  provided  with  suitable 
oil  levels  depending  on  the  type  of  oiling  system  in  use. 

Cylinder  Blocks  and  Cylinders. — The  function  or  purpose  of  the 
cylinder  is  to  provide  a  place  for  the  piston  to  move  up  and  down  in. 
In  it  is  placed  and  fired  the  charge  of  fuel  which  develops  the  power 
All  ports,  gaskets,  valves,  etc.,  must  be  made  to  fit  correctly  and  be 
kept  in  good  condition,  else  when  the  charge  is  fired  the  gases  will 
escape  from  the  cylinder  without  doing  their  duty  which  is  to  drive 
the  piston  down  in  the  cylinder.  The  piston  and  piston  rings  must 
be  well  fitted  to  the  cylinder  wall  which  must  be  perfectly  smooth 
and  true,  else  the  gases  will  escape  down  past  the  piston  into  the 
crank  case,  again  failing  to  fulfil  their  duty. 

Cylinders  are  cast  singly,  in  pairs,  in  sets  of  three,  or  in  blocks 
of  four  or  six.  The  water-cooled  single  cylinder  is  no  longer  used 
on   automobile   engines   to   any   extent,   although    it   is   perhaps   the 


118 


Automotive  Trade  Training 


Lett   Side   with   Concealed  Valve  Mechanism. 
Fig.  123.     National  Six,  I  Head. 

best  in  airplane  design  where  a  thin  steel  cylinder  has  a  still  thinner 
steel  shell  welded  over  it  to  provide  space  for  the  cooling  water.  In 
the  case  of  the  automobile  engine  these  spaces  for  the  water  are  cored 
out  in  the  engine  casting.  The  result  is  a  neat  efficient  cylinder 
block  casting. 


Functions  of  Engine  1 


ARTS 


119 


Engine  Types. — Engines  are  spoken  of  as  being  either  T,  L,  I, 
or  F  heads  due  to  a  general  resemblance  to  the  form  of  the  letters 
-when  the  engine  head  and  cylinder  casting  is  viewed  in  cross  section 
or  from  the  end.  The  L  is  considered  as  inverted,  and  in  point  of 
number  of  manufacturers  using  it  is  considered  most  popular.     Four 


Fig.  124.     Kelly  T  Head  Truck  Engine. 


120 


AuTOMOTUE  Trade  Training 


cylinder   L  head  engines  are  mentioned  as  well  as  four  cylinder  T 
head,  four  cylinder  I  head,  or  six  cylinder  T  head,  etc. 

Cylinder  Heads. — The  L  head  motor  is  perhaps  the  simplest  of 
all  designs.  It  is  very  popular  in  fours,  eights  and  twelves  where 
the  heads  are  usually  made  removable.  The  I  head,  or  as  termed  by 
some  manufacturers  the  "valve  in  head",  is  popular  in  sixes  and  in 
some  twelves.  The  term  "valve  in  head"  is  somewhat  misleading 
as  it  might  imply  that  no  other  construction  would  permit  of  valve  in 
the  head  construction.  As  a  matter  of  fact  motors  are  in  use  in 
which  the  valves  are  in  removable  L  heads.  The  term  'T  head" 
is  preferable.  The  T  head  has  usually  been  cast  with  a  solid  head 
t^lthough  this  method  is  not  imperative.  It  is  more  popular  in  sixes 
perhaps  than  elsewhere.  Since  two  cam  shafts  are  required  to 
operate  the  valves,  the  T  head  motor  is  more  expensive  to  build  than 
an  L  head  of  the  same  type.  Valve  size,  however,  is  not  limited. 
The  valves  of  all  other  types  of  motors  are  operated  from  the  single 
cam  shaft.  The  F  head  has  one  valve  overhead  and  one  in  an  L  pro- 
jection operated  from  the  valve  tapped  direct. 

In  considering  cylinder  block  design  and  construction,  it  is  well 
to  remember  that  any  engine  having  any  of  the  standard  numbers  of 

cylinders  might  use  any  of  the 
standard  forms  of  heads  cast  in- 
tegral or  removable,  and  that  it 
might  be  built  in  either  the  vertical 
or  V  type.  It  is  also  well  to  remem- 
ber that  price,  purpose,  accessibility 
and  manufacturing  practice  have 
held  and  will  continue  to  hold  de- 
sign within  certain  pretty  well  de- 
fined limits.  For  instance,  we  check 
off  the  items  removable  T  head  V 
type  motor.  Such  a  motor  could  be 
built,  but  for  obvious  reasons  is  not 
being  built. 

Cylinder  Care  and  Repair. — 
Proper  lubrication  of  cylinders  is 
the  best  safeguard  for  them  and  will 
do  much  to  prolong  their  life.  All 
the  features  tending  to  cause  over- 
heating of  the  engine  contribute  to 
rapid  wear  of  the  cylinders.  Proper 
care  of  the  engine  will  maintain 
them  in  condition  for  much  service, 
but  wear  is  bound  to  occur  to  some 
*"'*■  'contSwf  mS  l!'"""-  extent  due  to  the  side  pressure  of 


FcNCTioNS  OF  Engine  Parts 


121 


the  piston  when  it  is  under  the  stresses  of  compression  or  power 
development.  Another  feature  contributing  to  cyHnder  trouble  is 
the  constant  heating  and  cooling  of  the  cylinder  metal.  This  will 
induce  strains  in  the  cylinder  block  and  a  new  engine  is  almost  cer- 
tain to  come  out  of  true  to  some  extent  due  to  this  cause.  This 
trouble  may  be  corrected  rather  automatically  by  the  new  piston 
and  rings  wearing  to  their  seat  as  the  car  is  operated  over  the  first 


Inlet  f'alre--^ 

1 

^^,..,.-— Water  o 

jtlet 

W-^^Cuhnder  head 
1  ySparH  pluf  hole 
W^    Exhaust  ya//e 
1  /  Ignition  catplea 

^^Hh      '''j^'Distriifcitor 

\ 

jMIJ, 

0  ^ 

i 

prater  inlet "^^^H 

Cam  <fear         fW^W^Im, 

Fan  dr/ye--^      M-.  .>"/      i 

£j 

1 

?F^*^\ 

1 

% 

1 

^iFm 

Water  pump-^               J 
rrom  radiator 

Generator-^ 

.  -k 

Fig-.    120.     Reo    Removable    Head. 

500  or  1,000  miles.  To  correct  the  few  thousandths  of  an  inch  which 
normal  service  will  leave  a  cylinder  out  of  round,  it  is  frequently 
necessary  only  to  lap  in  a  new  piston,  or  if  the  trouble  is  of  a  more 
serious  nature,  it  may  be  necessary  to  rebore  the  cylinders  and  fit 
over-size  pistons.- 

Scored  Cylinders.— The  causes  which  result  in  scored  cylinders 
are  lack  of  lubrication,  foreign  substances  in  cylinder  as  carbon,  grit, 
spark  plug  porcelains,  broken  rings,  loose  piston  pins,  etc.  The  latter 
type  of  score  is  the  hardest  to  remedy.  A  score  is  a  cut  or  a  scratch 
formed  in  the  cvlinder  wall  as  the  piston  moves  up  and  down  in  the 


122 


Automotive  Trade  Training 


F/nncf  order l-d-4-S 


1 


Fig.  127.     Three   bearing  4  throw  crank   shaft   with  .pistons   and    rods   assembled    (Reo). 

cylinder.  To  remove  these  score  marks  it  may  be  sufficient  to  lap 
or  grind  them  out  using  an  old  piston  or  block  of  wood  for  a  dummy. 
If  severely  scored,  reboring  up  to  1/32"  oversize  will  usually  serve  to 
remove  it.     If  the  score  is  a  deep  one,  it  will  be  necessary  to  have 


\ 

'     i 

ir 

1 

-■    LlL.1 

i 

1 

1 

1 

L4l 

t-« 

Ik 

~ns 

y 

m^t 

,  1  |||W||e|"i 

-^ 

'""f^jjp*       ^.yw*^ 

J 

Fig.  128.     Four  bearing  five   throw  crank   shaft  with   pistons  and    rods   assembled    (Reo). 


the  score  filled  in  by  welding,  after  which  the  inside  of  the  cylinder 
will  have  to  be  machined  and  new  piston  and  rings  fitted.  The  most 
usual  practice  is  to  replace  the  badly  scored  cylinder  block  with  a 
new  block  as  it  is  the  one  certain  method  of  effecting  a  permanent 


Functions  of  Engine  Parts 


123 


repair.     This  may  mean  all  new  pistons  and  rings,  but  the  mechanic 
must  be  guided  by  circumstances  in  determining  this. 

Frozen  or  Bursted  Cylinders  and  Cylinder  Heads.— Some  cylinder 
blocks  are  protected  in  a  measure  from  freezing  by  means  of  small 
lead  or  steel  plugs  fitted  into  the  water  jacket.  When  expansion  due 
to  freezing  occurs  within  the  water  jacket,  these  plugs  may  be  forced 


Fig.  129.     Cadillac  Eight  Crank  Shaft  Assembly. 

out,  thus  relievin_g  the  internal  pressure,  as  they  are  designed  to  give 
before  the  jacket  cracks.  In  a  bad  case  of  freezing  they  may  not  save 
the  casting.  In  the  majority  of  cases  these  plugs  are  not  provided. 
A  badly  cracked  block  or  head  is  usually  replaced  with  a  new  one. 
Repairs  are  made  on  minor  breaks  by  several  methods. 

A  small  crack  or  break  may  be  repaired  by  using  X-Liquid, 
Neverleak,  or  similar  radiator  repair  compound  to  seal  it  from  the 
inside.  These  preparations  are  so  compounded  that  they  solidify  only 
when  steamed  out  through  the  crack.  No  harm  will  result  from 
leaving  them  in  the  radiator  a  time  after  the  leak  has  stopped. 

Crank  Shafts. — ^The  function  of  the  crank  shaft  is  to  receive  the 
power  delivered  to  it  by  the  piston  and  piston  rod,  from  the  cylinder, 
and  transmit  this  power  to  the  transmission.  While  doing  this  it 
must  be  so  arranged  as  to  care  for  all  cylinders  at  correct  intervals 
of  time. 

As  the  number  of  cylinders  have  been  increased  the  design  and 


124 


Automotive  Trade  Training 


construction  of  the  crank  shaft  has  necessarily  become  more  and 
more  compUcated.  High  speed  motors,  too,  have  exerted  a  decided 
pressure  toward  their  refinement.  The  strains  and  stresses  coming 
on  a  shaft  are  numerous  and  varied.     If  a  shaft  is  permanently  sprung 


=m^ 


Fig.   130.     Two   Bearing,   Three   Throw,   Counterbalanced    Crank    Shaft. 


Fig.  131.     Five  Bearing,  Four  Throw,  Counterbalanced  Crank  Shaft. 


Fig.  134.     Three  Bearing,   Six  Throw,   Counterbalanced   Crank   Shaft. 


Fig.  136.     Nine  Bearing,  Eight  Throw.  Counterbalanced  Crank  Shaft. 

a  few  thousandths  of  an  inch  out  of  true,  it  will  make  trouble  by 
binding  in  the  main  bearings.  While  it  must  be  heavy  enough  to 
resist  springing,  it  must  be  kept  as  light  as  possible  to  prevent  undue 


Functions  of  Engine  Parts 


125 


vibration  and  weight.     To  decrease  weight  and  insure  strength  addi- 
tional bearings  are  used.     More  main  crank  shaft  bearings  or  engine 


bearings  mean  a  longer  engine  as  well  as  additional  trouble  in  lining 
up  the  bearings. 


126  Automotive  Trade  Training 

Type  of  Crank  Shafts. — Crank  shafts  are  plain  or  counter- 
balanced. They  are  made  for  motor  car  engines  of  the  four,  six, 
eight,  and  twelve  cylinder  types.  Usually  drop  forged  steel  is  used. 
Sometimes  the  counterbalancing  weights  are  bolted  on  but  one-piece 
constriftction  is  considered  standard  practice  and  the  best.  The 
counterbalance  shafts  shown  in  Figs.  130  to  136  are  forgings  not 
machined.  In  speaking  of  crank  shafts  they  are  distinguished  first 
by  the  number  of  bearings,  second  by  the  number  of  throws,  third 
counterbalanced  or  plain,  and  fourth  by  the  number  of  cylinders  cared 
for.  In  the  case  of  the  Ford  engine  the  crankshaft,  Fig,  161,  is  a 
three  bearing,  four  throw  plain  shaft  for  a  four  cylinder  engine.  In 
the  case  of  the  Overland,  Fig.  192,  the  crank  shaft  is  a  two  bearing, 
three  throw  plain  crank  shaft  for  a  four  cylinder  engine.  In  the  case 
of  the  center  throw,  two  rod  bearings  are  accommodated  on  the  one 
throw.  Some  of  the  older  cars  used  a  five  bearing,  four  throw  plain 
shaft  for  four  cylinder  motors,  and  seven  bearing,  six  throw  shafts  for 
the  six  cylinder  motors.  This  was  usual  practice  where  the  cylinders 
were  cast  separate.  In  fact,  the  method  of  casting  cylinders  has  had  a 
very  definite  bearing  on  the  style  of  shaft  to  be  used.  If  main  engine 
bearings  are  to  be  used  between  each  pair  of  throws,  or  any  pair  of 
throws,  the  distance  between  cylinders  must  be  increased  a  distance 
equal  to  the  length  of  the  bearing.  This  has  a  very  decided  effect  on 
the  length  of  the  finished  motor.  With  the  pairing  and  tripling  of 
cylinders  in  block  casting  the  number  of  bearings  to  the  shaft  were 
decreased.  Where  a  center  bearing  is  used  on  a  four  cylinder  engine 
the  two  cylinders  in  the  center  of  the  block  are  farther  apart  than 
the  two  on  either  end.  In  the  case  of  the  six  having  four  main  bear- 
ings on  the  shaft  the  cylinders  are  again  paired  even  though  all  are 
cast  in  block,  while  if  three  cylinders  are  grouped  closely  together  at 
either  end  of  an  engine  group  cast  in  block,  the  shaft  used  will  have 
but  three  main  bearings.  These  statements  apply  particularly  to 
passenger  car  motors.  In  the  heavy  duty  motors  a  larger  number  of 
main  bearings  is  the  usual  practice.  In  the  case  of  airplane  motors 
where  single  or  separate  cylinder  castings  or  units  are  used  the  shaft 
is  usually  provided  with  one  more  main  bearing  than  there  are  throws 
to  the  shaft. 

Crank  Shafts  for  V  Type  Engines. — These  are  the  same  as  those 
for  the  four  or  six  cylinder  motors.  That  is,  a  shaft  similar  to  that 
used  in  a  four  is  used  in  an  eight,  and  a  shaft  similar  to  that  used  in 
a  six  is  used  in  the  twelve  cylinder  motors.  Usually  the  shaft  is 
heavier  and  main  bearings  larger.  Two  methods  are  used  in  attach- 
ing the  rods.     In  one  case,  as  the  Standard  8  shown  in  Fig.  117,  the 


Functions  of  Engine  Parts 


137 


Fig.  137.     Chandler  Crank  Shaft  Assembly. 
Hand.     Firing   Order  l-5-3-(»-2-4. 


Right 


rods  are  fitted  side  by  side 
while  in  other  cases,  as  that 
of  the  Cadillac  8  shown  in 
Fig.  129,  the  rods  are  yoked 
together. 

Technically  speaking 
there  are  no  such  crank 
shafts  as  four  cylinder  and 
six  cylinder,  but  rather 
four  or  six  throw  shafts  for 
the  four  or  six  cylinder 
motors.  To  determine  the 
type  of  shaft,  count  the 
number  of  main  bearings, 
and  the  number  of  throws, 
note  whether  plain  or  coun- 
terbalanced, and  the  num- 
ber of  cylinders  provided 
for  as  indicated  by  the 
number  of  rod  bearings  or 
crank  pins. 

Right  and  Left-Hand 
Shafts. — In  the  shafts  for 
the  fours  and  eights  there 
are  no  right  or  left-hand 
shafts,  but  in  those  of  the 
sixes  and  twelves  a  shaft 
may  be  either  right-hand  or 
%^  fe^C^BBE^^'^^M  Jk  left-hand  depending  on  the 

^•^  ^rar^UHMK     I    ■^'■W  relative  position  of  the  cen- 

ter throws  with  reference 
to  the  end  throws.  Place 
the  end  throws,  that  is 
number  one  and  six,  on  top 
dead  center.  When  facing 
the  engine  from  the  front 
the  student  can  determine 
whether  the  shaft  is  right 
•or  left-hand.  If  the  center  throws  are  to  the  right  side,  120  degrees 
advanced  over  the  end  ones,  1  and  6,  the  shaft  is  right-hand.  If  the 
center  throws,  3  and  4,  are  120  degrees  to  the  left,  the  shaft  is  left- 
hand.  A  right-hand  shaft  would  be  a  left-hand  shaft  if  it  were  turned 
end  for  end  in  the  engine.  Right  and  left-hand  has  no  reference  to 
the  direction  of  rotation  of  the  shaft  as  all  American  engines  are  made 
to  turn  to  the  right.     The  point  of  interest  here  is  the  bearing  the 


Fig.  138.     Chandler  Engine. 


l^y  AuTOMuTixE  Trade  Training 

shaft  construction  has  on  the  hring  order  of  the  engine  and  its  in- 
fluence on  cam  shaft  design. 

Six  Cylinder  Firing  Order. — The  most  popular  lirhig  order  for 
the  right-hand  shaft  is  1,  5,  3,  6,  2,  4,  while  for  the  left-hand  the  most 
popular  and  usual  order  is  1,  3,  5,  6,  4,  2.  There  are  several  other 
firing  orders  for  each  shaft,  but  the  best  distribution  of  power  im- 
pulses is  secured  with  the  above  orders.  Attempts  to  memorize 
liring  orders  lead  only  to  confusion  except  in  cases  where  only  one 
or  two  makes  of  engines  are  handled.  The  student  should  become 
so  familiar  with  the  engine  principle  that  a  study  of  piston  and  valve 
action  would  give  him  the  proper  firing  order  for  any  engine  in 
question,  in  first  hand  investigations. 

Crank  Shaft  Troubles. — Serious  crank  shaft  troubles  are  rather 
rare  as  a  rule.  Occasionally  a  shaft  may  be  broken  in  which  case  a 
new  one  is  usually  installed.  This  of  course  means  that  the  bearings 
must  be  fitted  to  it,  either  burned  in  or  scraped  in.  In  many  cases  it 
is  best  to  install  all  new  bearings  with  the  new  shaft.  Crankshafts 
may  be  welded,  but  the  practice  is  not  to  be  recommended  for  ordi- 
nary repairs.  In  a  case  where  no  new  shaft  is  available  it  is  standard 
practice. 

Foreign  substances  such  as  dirt,  grit,  steel  chips,  etc.,  sometimes 
work  their  way  into  the  bearings  and  may  score  the  shaft  very  badly. 
Failure  of  the  oiling  system  is  also  responsible  for  scored  and  Avorn 
bearings.  Upon  the  degree  of  injury  depends  the  method  of  repair. 
In  badly  scored  shafts  the  best  repair  is  to  have  the  work  done  on  a 
grinding  machine  in  a  recognized  machine  shop.  There  are  on  the 
market  certain  tools  for  hand  use  which  are  reliable  when  used  by  an 
experienced  mechanic. 

If  the  damage  to  the  shaft  is  of  a  minor  nature  the  repair  may 
be  effected  by  means  of  a  simple  lapping  or  grinding  tool  made 
from  two  blocks  of  wood  arranged  to  be  clamped  over  the  crank  pin 
or  journal  in  such  manner  as  to  secure  even  tension.  That  is,  it  would 
have  to  have  provision  for  adjustment  and  some  form  of  shim  must 
be  used  to  prevent  it  closing  down  on  the  low  spots.  A  steel  or  cast 
iron  lapping  jig  may  be  made  up  using  the  same  precautions,  or  an 
old  rod  with  its  babbitt  bearings,  shim  bolts  and  all  complete  may 
be  used  to  do  the  work. 

In  normal  service,  a  shaft  wears  gradually  due  to  the  fact  that 
more  pressure  is  exerted  at  certain  points  in  its  travel  than  at  other 
points,  as  when  receiving  the  power  impulse,  it  is  certain  to  wear 
out  of  round.  This  trouble  will  only  develop  after  a  great  deal  of 
normal  service,  and  can  be  corrected  as  suggested  above  and  in  the 
job  sheets. 

Main  Engine  Bearings. — The  function  of  the  main  engine  bear- 
ings, or  main  bearings  as  the  mechanic  terms  them,  is  to  carry  the 


Functions  of  Engine  Parts  129 

crank  shaft  in  proper  position  and  alignment  at  all  times  while  per- 
mitting it  to  turn  within  them  with  the  least  possible  amount  of  fric- 
tion and  loss  of  power,  which  is  being  transmitted  through  it  to  the 
transmission  from  the  cylinders.  These  bearings  are  what  is  known  as 
plain  bearings  in  most  cases.  In  certain  types  of  engines  ball  or 
antifriction  bearings  are  used,  but  they  have  never  become  popular 
for  general  use.  I'he  cause  of  this  is  likely  difficult  assembly,  noise 
and  lack  of  adjustment. 

The  main  bearings  are  almost  always  of  the  spHt  bushing  type. 
They  are  composed  of  a  white  metal  or  babbitt  bearing  surface 
mounted  in  a  bronze  back  or  cast  iron  back,  or  in  some  cases  directly 
in  the  engine  frame  and  bearing  caps.  The  bearing  made  up  of  the 
thin  layer  of  metal  sweated  onto  the  harder  metal  has  several  advan- 
tages. It  provides  a  greater  amount  of  metal  in  direct  contact  with 
the  shaft  which  serves  to  conduct  the  heat  generated  in  the  bearing 
away  more  readily.  It  is  a  well  known  fact  that  heat  will  not  travel 
from  one  piece  of  metal  to  another  as  readily  as  it  will  travel  and  be 
dissipated  within  its  own  mass  of  metal.  Witness  this  in  heating  a 
piece  of  metal  in  a  fire.  If  there  is  a  crack  present  it  is  shown  up 
immediately  due  to  the  fact  that  on  one  side  of  the  crack  the  metal 
may  show  a  red,  while  on  the  other  side  the  metal  will  still  remain 
black.  The  metals  may  even  lay  so  close  that  the  eye  cannot  detect 
the  crack  until  the  change  in  color  gives  evidence  of  it.  The  larger 
the  bearing,  the  more  frictional  heat  will  be  dissipated  by  it  and  the 
less  danger  of  that  bearing  being  burned  out. 

Burned  Bearings. — Bearings  are  burned  for  one  reason  only  and 
that  is  lack  of  dissipation  of  heat  generated  within  the  bearing,  or 
improper  cooling  -of  the  bearing.  Heat  within  a  bearing  is  due  to 
the  friction  of  the  rapidly  moving  or  turning  shaft  sliding  over  the 
surface  of  the  bearing  metal.  As  an  experiment  the  student  should 
try  rubbing  his  hands  briskly  together.  The  faster  they  are  rubbed 
the  warmer  they  become  until  they  even  become  rather  unpleasantly 
warm.  Addition  of  pressure  causes  still  more  heat  to  be  generated. 
This  heat  is  due  to  friction.  If  soap  and  water  are  used  between  the 
palms  while  continuing  the  rubbing,  the  heat  generated  is  barely 
noticeable.  This  is  due  to  the  fact  that  the  soap  and  water  form  a 
good  lubricant.  Water  only  will  relieve  some  of  the  friction,  but  not 
nearly  so  much  of  it  as  the  application  of  soap  and  water.  The  water 
might  be  said  to  be'  a  poor  grade  of  lubricant.  These  liquids  serve 
as  lubricants  because  they  prevent  the  hands  from  coming  in  contact 
with  one  another.  The  soap  particularly  serves  to  maintain  a  thin 
film  of  lubricant  between  the  palms,  thus  preventing  contact.  The 
same  condition  exists  in  a  well  lubricated  plain  bearing.  The  shaft 
does  not  actually  come  in  contact  with  the  bearing  metal,  but  rides 
on  the  oil  film.     Should  it  for  any  reason  actually  come  in  contact 


130 


Automotive  Trade  Training 


with  the  bearing  metal  in  a  dry  state  disaster  will  follow  in  a  few 
seconds.     In  this  case  the  bearing  is  said  to  burn.     The  internal  fric- 
tion generated  causes  the  metal  to  become  heated,  and  if  continued  it 
will   start   to   seize   on   the   shaft   in   small 
particles  and  drag  around  with  it.     As  the 
heat   continues   to   develop   it   will   become 
softer  and  softer  and  string  out  more  and 
more,  and  even  in  extreme  cases  of  burning 
will  become  so  hot  that  it  will  melt  and  run 
out  of  the  bearing  and  drop  down  into  the 
crank  case.     Long  before  this  happens  there 
is  usually  evidence  of  trouble,  although  it 

may  happen  so  quickly  in  the  case  of  sudden  failure  of  the  oiling 
system,  or  exhaustion  of  the  oil  supply,  that  little  warning  or  time 
is  given. 


Fig,    139.    Marmon    Main 
Engine  Bear'ng. 


CranM  ^shaft 


^fiaft 


Fig.  140.     Keo  Crank  Shaft  and   liod  Bearing. 

While  internal  heat  is  the  cause  of  bearings  burning  out,  the 
cause  of  the  heat  may  be  due  to  several  conditions.  Failure  of  the 
lubricating  system,  poor  quality  of  oil,  excessive  speed,  hot  weather, 
failure  of  the  engine  cooling  system,  foreign  matter  in  the  oil,  and 
overload  are  the  most  common  causes.  There  are  varying  degrees  of 
burns  from  that  in  which  the  bearing  metal  is  turned  a  blue  black 
up  to  the  point  where  the  bearings  seize,  and  the  final  point  when 
the  metal  flows  from  the  bearing.  Babbitt  melts  at  about  800  degrees. 
Depending  on  its  alloys  it  may  vary  either  way  from  this  point. 

Taking  Up  Main  Bearings. — This  is  a  necessity  at  intervals  vary- 
ing from  a  few  thousand  miles  up  to  thirty,  forty,  or  even  fifty 
thousand  miles  of  service,  depending  very  largely  and  directly  on  the 
skill  and  care  of  the  driver.     Much  depends  also  on  the  quality  of 


Functions  of  Engine  Parts 


lai 


oil  used.  When  this  work  is  found  necessary  great  care  and  good 
judgment  must  be  used.     Refer  to  Job  50. 

Scraping  in  Main  Bearings. — This  is  needed  as  a  rule  less  often 
than  taking  them  up.  It  is  usually  necessary  only  after  years  of 
normal  service  or  when  a  bearing  has  been  burned  or  otherwise 
abused.  It  is  a  tedious  job  and  one  requiring  judgment,  skill  and 
patience.  Naturally  it  is  also. expensive,  as  it  is  almost  always  neces- 
sary to  remove  the  engine  from  the  frame  and  rather  completely 
dismantle  it.     Refer  to  Job.  51  for  further  directions. 

Pistons. — The  function  of  the  piston  is  to  draw  in  the  gasoline 
and  air  on  its  downward  stroke,  compress  this  fuel  charge  on  its 
upward  stroke,  receive  the  power  as  developed  from  the  firing  of  the 
charge,  transmit  this  power  to  the  piston  rod  and  crank  shaft,  and 
on  its  second  up  stroke  free  the  cylinder  from  burned  gases. 

MATERIAL  AND  CONSTRUCTION 
Piston. — Pistons  are  usually  made  from  cast  grey  iron  although 
many  made  of  aluminum  or  aluminum  alloy  are  used.     One  of  the 


Pig.    141. 


Fig.  142. 


Marmon    2-Piece    Piston.    At    left,    Piston    Assembled.     At    Center, 
Aluminum   Head   and   Body.     At  right,   Iron   Skirt. 

developments  of  piston  design  is  that  of  the 
Marmon  where  an  iron  sleeve  is  used  over 
an  aluminum  body.  This  obviates  all  dan- 
ger of  piston  pin  scores.  The  two  parts  are 
assembled  from  the  inside,  using  cap  screws 
to  hold  the  parts  together.  While  alumi- 
num pistons  have  a  desirable  quality  of 
lightness,  the  expansion  to  which  they 
are  subject  when  heated  is  about  twice  that 
of  the  iron  pistons.  This  feature  contri- 
butes toward  a  noisy  motor  when  cold,  and 
loss  of  compression  in  cold  winter  months. 
Accordingly,  cast  iron  pistons  hold  rather 
steadily  in  favor  and  are  so  designed,  cast, 
and  machined  that  the  weight  is  not  exces- 
sive and  can  be  cared  for  in  balancing  up 
the  crank  shaft  and  fittings. 


Marmon  Piston  Rod 
Assembly. 


133 


Automotive  Trade  Training 


Piston  Clearance  Allowance. — Ordinarily  the  mechanic  does  not 
turn  down  or  machine  pistons.  However,  he  will  need  to  understand 
allowances  in  fitting  them  and  be  able  to  judge  clearance  rather 
accurately.  Special  allowances  are  made  in  special  cases,  but  a  rule 
safe  to  follow  in  the  regular  routine  of  w^ork  is,  for  cast  iron  allow 
.00075"  at  the  skirt  and  .002"  at  the  lands  of  the  piston  for  each  inch 
in  diameter  of  the  piston.     Double  these  amounts  for  aluminum. 

Piston  Rings. — The  function  of  the  piston  ring  is  to  seal  the  joint 
between  the  piston  side  and  the  cylinder  walls  at  all  times,  so  as  to 
prevent  loss  of  power  by  gases  escaping  down  past  the  piston.  At 
the  same  time  they  are  required  to  prevent  the  oil  from  working  up 
into  the  combustion  chamber  in  excess  quantities,  or  unburned  gaso- 
line working  down. 

The  individually  cast  and  machined  ring  made  from  grey  iron 
is  standard.  There  are  two  styles  of  plain  ring  with  two  types  of 
joint.  The  step  or  bevel  cut  eccentric  or  concen- 
tric rings  are  what  is  known  as  plain  type  piston 
rings  and  are  used  in  a  large  percentage  of  engines. 
The  advantage  of  the  eccentric  ring  lies  in  the  fact 
that  a  more  even  tension  is  maintained  over  the 
entire  circumference  of  the  ring.  It  might  be  com- 
pared to  the  Indian's  bow  which  had  the  thickest 
part  where  the  greatest  strain  came  in  use  and  per- 
mitted of  an  even  bending.  In  this  case  the  groove 
in  the  piston  for  the  ring  must  be  deep  enough  at 
all  points  to  accommodate  the  thickest  section  of 
the  ring.  This  groove  need  not  be  so  deep  in  the 
case  of  the  concentric,  but  the  pressure  will  not  be 
so  even  in  this  case  and  breaks  are  very  likely  to 
occur  at  the  point  opposite  the  joint  when  applying 
it  to  or  removing  it  from  the  piston.  Designers  are 
agreed  that  the  greatest  single  trouble  with  a  piston 
ring  is  the  liability  to  loss  of  power  through  loss 
of  gases  past  the  piston  ring  joint  or  lap.  To  over- 
come this  many  types  of  so-called  leak  proof  rings 
have  been  designed.  '''^ .l?f  andl'.T/'" 

_  .        .  _^ ,  .  Assembly. 

Leak  Proof  Rings. — Kmgs  purportmg  to  pre- 
vent leakage  of  gas  past  the  piston,  and  particularly  past  the  joint, 
are  numerous.  .  Many  excellent  designs  and  excellent  rings  may  be 
found.  Because  the  trade  name  of  one  of  the  oldest  and  best  of  this 
type  of  ring  was  "Leak  Proof",  mechanics  have  come  to  class  all 
specially  designed  rings  of  more  than  one-piece  construction  leak- 
proof  rings.  The  main  point  desired  is  to  prevent  gas  escaping  past 
the  ends  or  through  the  joint. 


Functions  of  Engine  Parts  133 

Two  methods  are  used  in  attempting  to  obtain  the  desired  result. 
Either  some  special  form  of  lap  is  used,  or  the  ring  is  made  in  two 
or  three  pieces,  with  the  laps  so  arranged  that  there  is  little  chance 
for  leakage  of  gas  through  them. 

Generally  speaking,  that  ring  is  best  which  is  best  fitted  to  the 
cylinder  wall  and  the  piston  ring  grooves  irrespective  of  the  type  of 
lap.  Certain  types  of  rings  do  give  better  results  in  certain  motors 
granting  workmanship  is  equal  in  each  case. 

Refer  to  job  sheets  for  data  on  fitting  rings. 

Piston  Pins. — The  function  of  the  piston  pin  is  to  hold  the  piston 
and  the  piston  rod  together  and  in  proper  relation.  It  forms  a  flexible 
joint  with  an  oscillating  movement  which  permits  the  proper  move- 
ment of  parts  to  transmit  power  from  the  cylinder  to  the  crank  shaft. 
Piston  pins  are  made  from  a  high  grade  of  steel  machined  and  hard- 
ened, after  which  they  are  ground  to  size.  They  are  made  to  size 
within  very  close  dimensions  and  can  usually  be  obtained  in  over- 
sizes  which  range  from  .001",  .002",  .003",  .005",  .0075",  .010"  oversize. 
The  pins  are  usually  made  hollow  because  they  must  be  made  light, 
and  at  the  same  time  have  sufficient  bearing  surface  to  withstand 
tremendous  hammering  and  pounding  while  carrying  heavy  loads. 

Piston  Pin  Fit. — The  piston  is  cast  with  bosses  to  carry  the  pin. 
Sometimes  provision  is  made  for  bushing  these.  The  pin  fits  into 
these  bosses  in  a  close  manner,  .001"  being  sufficient  clearance,  unles.^ 
the  lubrication  is  force  feed  when  .002"  to  .003"  is  allowed.  This 
:lose  fit  is  needed  to  prevent  a  piston  pin  knock  as  the  piston,  when  it 
reaches  upper  or  lower  dead  center,  must  be  stopped  and  the  direction 
Df  drive  reversed.  If  there  should  be  any  perceptible  play,  the  con- 
tinual action  of  the  piston  on  the  pin  would  quickly  result  in  sufficient 
wear  to  cause  a  knock  to  be  heard.  After  this  point  is  reached  the 
fcvear  is  more  rapid  because  the  more  the  play  the  greater  the  force 
Df  the  knock  and  consequently  the  more  rapid  the  wear.  Instead  of 
1  rotary  movement  the  pin  has  an  oscillating  movement  which  results 
n  uneven  wear.  This  appears  on  the  top  and  bottom  of  the  pin  and 
n  the  same  points  with  reference  to  the  piston  pin  bushings. 

Securing  the  Piston  Pin. — More  badly  scored  cylinders  result 
:rom  loose  piston  pins  than  from  any  one  other  cause.  A  piston  pin 
score  is  very  difficult  to  repair,  although  it  can  be  done  by  welding 
Dr  filling  in  with  certain  metals.  The  block  is  usually  replaced  with 
I  new  one.  To  prevent  scoring  means  that  the  pin  must  be  so 
secured  in  the  piston  that  it  is  impossible  for  it  to  work  endways 
IS  it  is  the  end  of  the  pin  projecting  past  the  piston  into  the  cylinder 
,vall  which  causes  piston  pin  scoring.  Numerous  methods  of  secur- 
ng  the  pins  in  place  are  in  use  as  the  setscrew  method,  the  dowel 
3in  method,  the  bolt  method,  etc.  Whichever  method  is  used  is  also 
:)rovided    with    some    lock    to    prevent   it    working    loose,    and    out. 


134 


Automotive  Trade  Training 


Greatest  care  should  be  used  to  see  that  the  fastening  device,  be  it 
wire,  washer,  cotter  key,  or  what  not,  is  in  first  class  condition.  It 
is  not  a  good  plan  to  use  many  of  these  devices  the  second  time  as 
bending  has  weakened  them. 

Connecting  Rods. — The  usual  style  of  the 

^  connecting    rod    is    H    section    drop    forgings, 

although  in  the  full  force  feed  round  hollow 
rods  are  used  at  times  to  facilitate  oiling.  In 
this  case  the  oil  is  forced  up  through  the  centei* 
or  hollow  of  the  rod  from  the  crank  shaft  to 
the  piston  pin.  In  case  of  full  force  feed  oiling 
systems  where  the  H  section  rod  is  used,  a 
copper  tube  is  run  up  on  the  outside  of  the  rod 
to  carry  the  oil.  The  drop  forged  type  gains 
slightly  in  weight  and  strength  from  the  piston 
toward  the  crank  shaft.  The  function  of  the 
piston  rod,  or  rod,  as  the  mechanic  calls  it,  is  to 
convert  the  reciprocating  motion  of  the  piston 
into  the  revolving  motion  of  the  crank  shaft,  at 
the  same  time  transmitting  power  from  the  pis- 
ton to  the  shaft  as  on  the  power  stroke,  or  from 
the  shaft  to  the  piston  as  on  the  compression 
stroke.  It  must  be  strong  to  resist  end  thrust, 
and  light  to  prevent  undue  vibration. 

Piston  Pin  Bearing, — The  piston  pin  is 
carried  in  the  upper  end  of  the  rod.  At  times 
the  rod  is  designed  to  carry  the  piston  pin  bush- 
ing or  bearing  in  the  upper  end.  A  close  run- 
ning fit  is  provided  for  the  pin  in  the  bushing, 
while  a  press  fit  is  provided  in  the  piston  bosses 
Pig.  144.  Rochester  for  the  piston  pin  ends.  It  is  good  practice 
^^^Assembiy. ^"^  where  this  type  of  construcion  is  used  to  secure 

one  end  of  the  pin  only,  leaving  the  other  end  free  to  expand  when 
heated  without  distorting  the  piston. 

More  often,  however,  the  pin  is  secured  in  the  iipper  end  of  the 
rod  and  the  bearings  are  in  the  piston  bosses.  Reference  is  made  to 
this  method  in  Job.  53. 

Rod  Bearings. — The  lower  end  of  the  piston  rod  carries'  the  rod 
bearings.  This  is  of  the  split  bushing  type,  also  known  as  a  "plain 
bearing".  It  is  very  similar  to  the  main  bearings.  Adjusting  and 
scraping  of  rod  bearings  is  somewhat  easier  than  that  of  the  main 
bearings  since  they  are  more  accessible  and  may  be  handled  in- 
dividually, and  the  fitting  of  one  has  no  influence  on  any  other  as 
is  the  case  in  the  main  engine  bearings.     Rod  bearings  will  be  badly 


Functions  of  Engine  Parts  135 

worn  or  burned  if  run  dry  or  even  partially  dry.  A  very  disagreeable 
knock  will  develop  in  this  case.  The  bearing  should  be  adjusted 
immediately  any  evidence  of  wear  is  noticed. 


Fig.    145.     Rochester   Valve   Mechanism.    " 

Cam  Shafts. — The  function  of  the  cam  shaft  is  to  open  the  valves 
at  correct  intervals   of  time,  hold   them  open  the  correct  length  of 


Fig.  146.    Reo  Cam   Shaft  and   Related   Parts. 


136 


Automotive  Tkaue  Training 


time,  and  permit  them  to  close  at  the  correct  moment.  The  design 
of  the  crank  shaft  must  be  taken  into  consideration  in  determining 
the  firing  order  of  the  engine.  The  design  of  the  crank  shaft  and  the 
desired  firing  order  of  the  engine  are  the  determining  factors  in 
designing  the  cam  shaft. 

What  the  repairman  needs  to  remember  is  that  the  firing  order 
of  any  engine  is  fixed  when  the  design  of  the  cam  and  crank  shaft 


Fig.   147.     Rochester  Deusenberg   Cam    Shaft. 

is  determined  on  by  the  designer  and  manufacturer,  and  that  there- 
after there  is  only  one  firing  order  for  that  engine.  If  it  is  found 
necessary  to  determine  the  firing  order  of  any  engine,  the  action  of 
the  valve  lifters  as  they  raise  and  ride  on  the  cams  of  the  cam  shaft 
will  be  the  readiest  source  of  information. 


Fig.  148.     Cadillac  8  Valves  and  Cam   Shaft   Arrangement. 

Two  Valves  Per  Cylinder. — Always,  in  the  poppet  type  engine 
valve  design,  one  valve  is  provided  for  intake  and  one  for  exhaust 
for  each  cylinder  of  the  engine.  In  some  cases  four  valves  per 
cylinder  are  provided,  two  for  intake  and  two  for  exhaust.  Engines 
using  four  valves  per  cylinder  are  known  as  "dual  valve"  engines. 

The  intake  valve  opens  on  a  down  stroke  of  the  piston  in  its 
respective  cylinder,  while  the  exhaust  valve  was  open  on  the  previous 
up   stroke.     For   two   strokes,   or   one   revolution,   or   one-half   cycle 


Functions  of  Engine  Parts 


137 


4H^ 

f 

' 

Fiji-.     14i).       MiiniKi 
Valve  Mechanism. 


neither  valve  is  opened.  This  is  during  the  com- 
pression stroke  and  the  power  stroke  as  they  follow 
in  succession  after  the  intake  stroke.  The  valves 
are  actuated  by  the  cams  on  the  cam  shaft  which 
the  engine  timing  gears  hold  in  fixed  relation  to 
the  crank  shaft  while  driving  it  at  one-half  crank 
shaft  speed. 

In  the  operation  of  the  valves,  the  valve  lifter 
riding  on  the  cam  is  caused  to  raise  on  the  cam 
nose,  thus  raising  the  valve  from  its  seat  by  push- 
ing up  on  the  bottom  of  the  valve  stem  (in  the  case 
of  an  L  or  T  head  motor).  The  distance  the  valve 
raises  off  the  seat  is  about  5/16"  to  }i".  The 
length  of  time  it  is  held  open  depends  on  the  design 
of  the  cams. 

Cam  Shaft  Drive. — Two  methods,  both  posi- 
tive, are  in  use  for  driving  the  cam  shaft  from  the 
crank  shaft.  One  is  by  the  use  of  timing  gears 
and  the  other  by  the  use  of  the  silent  chain.  In 
order  that  the  correct  speed  relation  or  ratio  be 
maintained  at  all  times,  it  is  necessary  that  the  tim- 
ing gear  on  the  crank  shaft  have  just  one-half 
as  many  teeth  as  the  timing  gear  on  the  cam  shaft. 


i 

^^^^^K**  *'^^Hflp*'«i^B'   '' 

t 

J  1;  ly  i'  i 

L. 

;  «y^ 

i^EK^mJ^K]:!  iii^ 

H'  z\ 

S  t  !5k!^  iSl-l,!yi!^i^^'^^^1H 

'"^'      '^^^^^R^ 

Fig.  150.    Phantom   photo   of  typical   Stearns   Knight   motor,   showing  sleeve-valves  and 

their   operating   mechanism. 


138 


Automotive  Trade  Training 


thus  giving  a  gear  ratio  of  2  to  1.  The  student  will  need  to  famil- 
iarize himself  with  the  statement  of  the  travel  of  the  two  shafts  in 
degrees  as,  while  the  gear  ratio  is  2  to   1,  the  one  travels  through 


•'Exhaust  Stroke 


— Intake  Stroke 


—Explosion  or  Power  Stroke  —Compression  Stroke 

Fig.  151.     Willys-Knight  8  Sleeve  Valve  Engine  Section.     Note  position  of  parts  in 
each  stroke  of  the  cycle. 

only  one  half  of  a  circle,  or  180  degrees,  while  the  other  travels 
through  a  full  circle,  or  360  degrees.  This  is  true  of  all  four  cycle 
engines  and  must  be  understood  thoroughly  by  the  student  to  grasp 
the  actual  theory  and  process  of  valve  timing. 


Functions  of  Engine  Parts 


139 


Fig.  152.     Reo  Valve  Mechanism. 


Fig.   153.    Buick   Self   Lubricating   Valve  Mechanism. 


140 


Automotive  Trade  Training 


Fig.  154.     Reo  Cam  Shaft. 

Valve  Lifters. — Most  valve  lifters  are  made  with  a  large  seat  or 
base  to  rest  on  the  cam.  This  base  is  hardened  to  resist  v^ear.  The 
upper  end  of  the  lifter  w^hich  rests  immediately  under  the  valve  stem 
is  provided  with  a  screw  for  adjustment.  This  permits  of  setting  the 
lifter  to  compensate  for  wear  either  within  the  lifter  on  the  cam  or 
the  valve,  as  well  as  for  expansion 
of  the  valve  stem  due  to  heat  from 
the  engine.  Valve  lifters  seldom  give 
any  trouble  except  for  a  loose  or  bad 
adjustment. 

Valves. — The  poppet  type  valve 
is  in  use  in  a  very  large  percentage 
of  the  automotive  equipment  en- 
gines. Other  styles  of  construction 
have  at  times  proven  successful, 
but  in  no  instance  have  they  been 
found  to  possess  enough  good  fea- 
tures to  offset  the  cheapness  and 
desirable  points  of  design  of  the 
poppet  valve. 

Valves  are  made  from  steel  in  one  piece,  and  with  a  steel  stem 
and  cast  iron,  or  other  special  head.  Certain  special  steels  as  tungs- 
ten or  nickel  steel  are  used  because  of  the  fact  that  experience  has 
shown  that  these  metals  will  resist  the  high  temperatures  best.  In 
some  cases  the  inlet  valves  and  the  exhaust  valves  are  made  from 
different  materials,  each  selected  with  a  view  to  the  conditions  under 
which  they  do  their  work. 

Valve  Grinding. — Under  service  conditions  a  variety  of  causes 
result  in  valve  wear  which  makes  necessary  the  reseating  of  the  valve 
on  the  valve  seat.  This  is  done  either  by  grinding,  or  in  cases  of 
extreme  wear,  by  the  use  of  the  reseating  tools  followed  by  grinding. 
Conditions  contributing  to  valve  trouble  are  the  excessive  heat  which 
very  often  causes  warping  of  the  valve  head.  Constant  action  as  it  is 
dropped  or  forced  onto  the  valve  seat  will  cause  uneven  wear  of  the 
head.  The  constant  rise  and  fall  of  the  valve  in  the  valve  stem 
guides  under  strong  spring  pressure  will  cause  uneven  wear  and 
ultimately  result  in  improper  seating  of  the  head,  as  well  as  leaking 


Fig-.  1")").     Studebaker  Bevel  Timing 
Gears. 


Functions  of  Engine  Parts  141 

past  the  intake  valve  stems  causing  uneven  operation  of  the  motor. 
Carbon  and  heat  will  pit  the  valve  seat.  Carbon  under  the  valve 
head  will  allow  the  flow  of  gases.  All  of  these  troubles  contribute 
to  a  loss  of  power  as  the  compression  is  imperfect  and  the  power 
impulse  loses  force  due  to  lack  of  compression  and  a  loss  of  the 
exploded  gases  past  the  leaky  valves.  Invariably,  or  almost  so,  the 
intake  valves  require  less  attention  than  the  exhaust.  Several  causes, 
contribute  to  this.  The  intake  valve  deals  with  a  clean  cool  mixture.. 
The  exhaust  valve  handles  a  flaming,  hot,  dirty,  smoking,  carbon 
depositing  gas. 

When  the  engine  has  been  in  operation  a  length  of  time  sufficient 
to  produce  the  results  and  conditions  noted  above,  the  valves  are 
ground,  valve  lifters  or  tappets  adjusted,  and  carbon  removed,  thus 
restoring  to  the  motor  its  usual  power.  As  to  the  actual  need  of 
valve  grinding  as  opposed  to  the  imaginary  need  of  valve  grinding 
much  might  be  said.  Because  of  the  fact  that  valve  grinding  is  com- 
paratively simple  it  is  one  of  the  first  things  the  amateur  turns  to.. 
Some  believe  it  a  panacea  for  all  engine  ills.  While  it  is  true  that 
leaky  valves  do  cause  much  trouble,  it  is  also  true  that  carbon  causes 
the  leaking  valves  and  a  multitude  of  other  ills  which  will  be  relieved 
and  corrected  by  its  removal.  Valves  may  require  reseating 
after  50  miles  of  service  or  after  50,000  miles  of  service.  When  they 
need  the  reseating  they  should  have  it.  Frequent  grinding  wears 
away  the  head  and  the  valve  seat  in  the  combustion  chamber,  making 
the  actual  point  of  contact  wide  and  hard  to  maintain.  As  the  valve 
head  is  made  thinner  and  thinner  it  warps  and  burns  more  and  more 
easily.  Most  valves  are  machined  with  the  face  of  the  seat  at  an 
angle  of  45  degrees  with  the  stem,  although  some  are  60  degrees. 

Rocker  Arms. — In  the  case  of  the  I  head  motor  the  valves  are 
located  over  the  cylinders  in  the  head  in  an  inverted  position  with 
reference  to  the  valves  in  the  L  or  T  heads.  This  necessitates  the 
introduction  of  a  rocker  arm  mounted  on  the  top  of  the  head  to 
receive  the  lift  from  the  push  rods  resting  on  the  valve  Hfters.  The 
rocker  arm  receives  this  lift  on  its  outer  end,  and  as  it  rocks  on  its 
rocker  pin  it  forces  the  inner  end  down  on  the  upturned  end  of  the 
valve  stem,  thus  opening  the  valve.  Valve  timing  is  identical  with 
the  L  head  motor.  This  arrangement  of  valves  is  conceded  by 
engineers  to  make  a  motor  having  in  it  a  bit  more  power  than  any 
other  construction.  It  is  not  as  simple  nor  as  sturdy  a  type  of  con- 
struction, as  the  number  of  small  moving  parts  is  greatly  increased. 
The  greatest  difficulty  is  to  keep  these  parts  properly  lubricated. 
Complete  enclosure  of  parts  has  done  much  to  correct  lubricating 
faults. 

Knight  Type  Engines. — One  form  of  valve  construction  which 
has  proven  itself  the   equal  of  the  poppet  valve  type,  and  even  in 


142 


Automotive  Trade  Training 


point  of  valve  care  a  bit  superior,  is  the  Knight  Sleeve  Valve  motor. 
The  Stearns  Knight,  shown  in  Fig.  150,  is  typical  of  all  Knight  motors 
as  all  are  made  under  the  same  Letters  Patent.  Instead  of  the  piston 
being  fitted  into  the  cylinder,  the  cylinder  is  fitted  with  an  outer  and 
inner  sleeve.  The  piston  is  fitted  into  the  inner  sleeve.  The  two 
sleeves  are  made  a  free  sliding  fit  and  in  their  upper  ends  ports  are  pro- 
vided for  the  intake  and  exhaust  mechanism.  As  will  be  noted 
in  the  cut,  the  sleeves  are  operated  for  short  up  and  down  strokes  by 
means  of  eccentric  rods  worked  from  the  eccentric  shaft.  This  shaft 
takes  the  place  of  the  usual  cam  shaft.  At  certain  points  in  sleeve 
valve  travel  the  intake  ports  are  opened  permitting  a  charge  to  enter. 
The  ports  are  then  closed  and  remain  closed  until  after  the  compres- 
sion and  power  strokes,  when  the  movement  of  the  valves  or  sleeves 
is  so  timed  as  to  bring  the  exhaust  ports  or  slots  in  line  and  permit 
the  exhaust  of  the  burned  gases.  Valve  timing  is  identical  with  all 
four  stroke  cycle  motors  in  that  the  eccentric  shaft  travels  at  one-half 
crank  shaft  speed,  and  the  intake  must  be  set  to  open  at  five  to  ten 
degrees  past  the  top  dead  center. 

Valve  Timing. — The  student  has  previously  considered  the  four 
cycle  principle.  He  has  learned  the  various  strokes.  For  theoreti- 
cal purposes  the  stroke  and  operation  were  considered  as  identical. 
That  is,  the  intake  consumes  exactly  one  stroke,  or  one -half  revolu- 
tion, and  the  compression,  power,  and  exhaust  each  just  one  stroke 
or  one-half  revolution,  or  180  degrees  crank  shaft  or  flywheel  travel. 
Actually  these  operations  vary  considerably  from  180  degrees,  one- 
half  revolution,  or  one  stroke. 

For  instance,  good  practice  does  not  open  the  intake  valve  <>ii 
T.  D.  C,   (Top  Dead  Center),  but  about  ten  degrees  past  T.  D.  C. 

in  flywheel  travel.  This  valve  does 
not  close  at  B.  D.  C,  (Bottom  Dead 
Center),  but  at  about  35  degrees 
past  B.  D.  C.  This  gives  on  an 
average  about  205  degrees  for  in- 
taking  the  fuel  charge. 

From  the  time  the  intake  valve 
closes  to  T.  D.  C,  the  cylinder  is  on 
the  compression  stroke  or  operation. 
This  represents  a  distance  of  about 
145  degrees  of  flywheel  travel. 

At  the  end  of  the  compression 
stroke  the  charge  is  fired,  the  piston 
being  forced  downward.  When  the 
flywheel  has  traveled  from  T.  D.  C. 
to  about  45  degrees  from  B.  D.  C, 
or  through  135  degrees,  the  exhaust 


Pig.  156.     Studebaker  Valve  Mechanism 

Valves   inclined   at   20  degree  angle. 

Bell    Crank    Lift. 


Functions  of  Engine  Parts 


143 


valve  is  opened  and  remains  open  until  B.  D.  C.  has  been  reached  and 
passed  on  up  through  the  full  180  degrees  to  T.  D.  C,  and  to  about 
five  degrees  past  when  it  closes.  In  a  few  more  degrees  travel  the 
cam  shaft  opens  the  inlet  valve  again.  The  power  stroke  is  about 
135  degrees  long  as  measured  in  crank  shaft  or  flywheel  travel,  the 
exhaust  about  230  degrees,  while  the  intake  is  145  degrees,  and  the 


Fig.   157.    Maxwell   Timing   Gears. 

compression  about  205  degrees.  With  a  minus  valve  lap  of  five 
degrees  added  the  sum  of  720  degrees  is  obtained,  which  is  equal  to 
and  represents  two  revolutions  of  crank  shaft  and  flywheel,  four 
strokes  or  operations,  and  one  complete  cycle.  During  this  time  the 
cam  shaft  has  traveled  through  one  complete  revolution  or  180 
degrees.  Each  valve  has  been  opened  just  once.  The  time  the  valves 
remain  open  is  determined  by  the  design  of  the  nose  of  the  cam,  the 
exhaust  cam  having  a  broader  nose  than  the  intake  cam.  The  time 
at  which  the  valves  open  is  determined  by  the  setting  of  the  cam 
shaft  in  relation  to  .the  crank  shaft.  Sumjnarizing  the  above  figures 
gives  the  following  table  which  is  representative  of  the  average  in 
valve  timing  and  not  of  any  specific  engine : 

1  revolution  equals  ^  cycle,  equals  360  degrees  travel. 

2  revolutions  equal  1  cycle,  equals  720  degrees  travel: 

Intake,  first  quarter  cycle  or  stroke  equals 205  degrees  travel 

Compression,  second  quarter  cycle  or  stroke  equals  145  degrees  travel 

Power,  third  quarter  cycle  or  stroke  equals 135  degrees  travel 

Exhaust,  last  quarter  cycle  or  stroke  equals 230  degrees  travel 

Minus  valve  lap,  equals 5  degrees  travel 

One  completed  cycle  totals 720  degrees  travel 


144 


AuTOMOTiNE  Trade  Training 


Fig.  158.     Right   and    Left   Side   Views   of   Rochester   Model   G   Deusenberfr   Type    Engiiu'. 
JJure    414",    Stroke    6".     Note    Horizontal    Valve    Aftion. 


Valve  Lap. — ^This  is  the  term  applied  to  the  condition  of  valve 
action  with  reference  to  the  closing  of  the  exhaust  valve  and  openincT 
of  the  intake  valve.  Either  a  plus  or  minus  lap  is  possible.  With 
a  plus  lap  both  are  held  open  for  a  few  degrees  of  flywheel  travel  at 
the  same  time.  In  rare  cases  this  will  be  as  much  as  from  ten  to 
twenty  degrees.  The  minus  lap  rarely  exceeds  ten  degrees  and  is 
more  often  less  than  five. 

As  stated  previously,  these  figures  are  fairly  representative  of 


Functions  of  Engine  Parts 


145 


the  general  average.  In 
actual  valve  timing  where 
no  mark  is  on  gears,  or 
old  gears  are  being  re- 
placed with  new  ones,  it 
need  not  be  expected  that 
every  type  of  motor  will 
correspond  exactly  to  the 
figures  given.  In  timing 
up  some  engines,  especial- 
ly those  with  coarse  gear 
teeth,  it  would  likely  be 
impossible  to  more  than 
approximate  these  figures^ 
Since  valve  timing  Avith 
respect  to  setting  of  the 
timing  gears  together  is 
usually  done  with  the  ex- 
haust valve  just  closing- 
and  the  intake  just  open- 
ing, one  tooth  out  of  time 
either  way  would  be  so 
obvious  that  there  would 
be  little  room  for  doubt  as 
to  when  the  exact  teeth 
were  in  mesh  to  have  the 
exhaust  closing  at  about 
five  degrees  after  T.  D.  C, 
and  the  intake  opening 
about  five  degrees  later. 
When  timing  any  engine 
care  must  be  used  to  have 
the  piston  in  the  cylinder 
Mechanism  with  the  cover  being  worked  from,  us- 
ually No.  1  on  top  dead 
center. 
Another  method  of  timing  valves,  quite  as  reliable  as  the  one 
given  above,  is  that  given  with  reference  to  the  timing  of  the  Hudson 
Super-Six  in  Job  63.  Here  distance  is  measured  by  inches  of  piston 
travel  as  well  as  inches  of  flywheel  travel. 

Degrees  Converted  to  Inches. — While  it  may  be  difficult  to  figure 
the  number  of  degrees  within  a  certain  space  on  the  flywheel  by  the 
use  of  a  protractor,  it  is  comparatively  easy  to  find  the  number  of 
degrees  included  in  one  inch  of  the  flywheel  circumference.  With 
a  tape  line  measure  the  distance  around  the  flywheel  and  divide  this 
into  360  degrees. 


Fig.   150.     National  Yalv 

plates   removed.     Lnbrii-ation  'is  effected  through 
the  hollow  rocker  arm   shaft. 


146 


Automotive  Trade  Training 


ROCKER  ARM  OIL  WICK 


ROCKER  ARM  COVER. 


ADJUSTING  BALL 
LOCK  NUT 

WATER  JACK 


SPARK  PLUG  COVER 

COMBUSTION 
SPACE 

PUSH  ROD 


VALVE 

PUSH  ROD  COVER 


CYLINDER. 
VALVE  LIFTER  CAP 

VALVE 

LIFTER  GUIDE  CLAMP- 
VALVE  UFTER  SPRING 
VALVE  UFTER  GUIDE 
VALVE  UFTER 

CAM  ROLLER  PIN 
CAM  ROLLER 

CAM  SHAFT 


EXHAUST 
MANIFOLD 

INTAKE 
MANIFOLD 

HOT  AIR 
CHAMBER 


CONNECTING  ROD 

CRANK  CASE 

CRANK  SHAFT 


Fig.   160.     Buick   Valve  Mechanism   ami    related   parts. 


Functions  of  Engixe  Parts 


147 


JOB  48.     FITTING  OR  TAKING  UP  CONNECTING  ROD   BEARINGS 

1.  The  following  directions  apply  equally  to  the  work  whether  it  is  done 
for  practice  or  in  actual  service  work. 

2.  Remove  the  rod  from  the  crank  shaft. 


3.  Note  how  assembled  so  as  to  insure  proper  reassembly. 

4.  Learn  also  and  note: 

a.  Front  end  of  crank  shaft. 

b.  How  flywheel  would  be  fastened, 

c.  Cam  shaft  side, 


148 


Automotive  Trade  Training 


d.  Number  of  main  bearings, 

e.  Number  of  throws  on  shaft, 

f.  Number  of  cylinders  shaft  would  care  for. 
Adjusting  a  bearing. 

a.  On  removing  the  rod  cap  you  note  a  number  of  shims  are  found. 

b.  These    should   always   be   retained   in   order   that   on    reassembly 

they  go  back  in  original  position. 

c.  Remove  several  thin  shims  and  try  reassembling  the  rod.     Is  it 

too  tight? 

d.  Keep  adjusting  shims  until  you  have  learned  what  too  tight  is. 

Have  it  inspected. 

e.  Replace    shims    until    you    learn    what    too    loose    is.     Have    it 

inspected. 

f.  Now  adjust  for  proper  fit  as  though  it  were  to  go  into  the  car 

and  you  were  the  sole  judge  of  correctness.     Have  it  inspected 
and  rated, 
g.     Always  be    sure   to   place   a   coat   of   oil   on   the   bearing  on   final 
assembly.     To  neglect  this  may  burn  out  a  bearing  before  the 
oil  reaches  it. 


Fig.    162.    Packard    Engine.     Note    method    of    assembling-    rod    bearings. 
Als:)   size   of  main   bearings. 

JOB  49.     SCRAPING  CONNECTING  ROD  BEARINGS. 

1.  The  following  methods  should  be  used  whether  the  work  is  done 
with  the  shaft  out  of  the  engine  or  with  the  shaft  in  position  in  the  engine. 
In  the  first  case  the  piston  must  be  maintained  at  right  angles  to  the  shaft. 

2.  Remove  the  rod  cap  and  shims. 

3.  Treat  the  crank  pin  of  the  shaft  with  a  thin  coat  of  bearing  blue. 

4.  Clamp  the  rod  to  the  shaft  having  in  the  proper  amount  of  shims. 

5.  Rotate  the  rod  on  the  shaft  for  three  or  four  turns. 

6.  Remove  the  rod. 

7.  Note  bright  spots  on  the  bearing  and  take  it  to  the  instructor  for 
explanation. 


Functions  of  Engine  Parts  149 

S.  Secure  a  bearing  scraper  and  with  this  remove  the  bright  spots  which 
are  the  high  points. 

9.  Continue  this  operation  until  you  have  at  least  a  75  per  cent  bearing 
which  will  be  indicated  by  the  frequency  or  closeness  of  the  spots.  In  a  well 
fitted  bearing  the  blue  will  appear  evenly  distributed  over  the  bearing  after 
fitting. 

10.  It  may  be  necessary  to  remove  or  add  shims  in  work  of  this  nature 
from  time  to  time. 

11.  When  finally  fitted,  the  weight  of  the  piston  on  the  rod  should  be 
sufficient  to  carry  the  rod  slowly  downward  when  started  from  the  top,  but  not 
loose  enough  to  oscillate  back  and  forth.  In  fitting  rods  in  an  engine  where 
this  test  cannot  be  made,  a  fair  idea  of  their  correctness  may  be  secured  by 
tapping  the  rod  side  to  side  with  a  hammer.  A  medium  blow  should  cause  it 
to  move  endwise  on  the  crank  pin.  If  it  does  not  move,  it  is  too  tight.  If  it 
can  be  shoved  with  the  hands  it  is  too  loose. 

Caution:  Enough  shims  must  be  used  to  hold  the  cap  in  the  correct 
position  when  the  nuts  are  drawn  up  tight.  Never  release  nuts  to  get  the  right 
clearance.     Always  add  shims  and  draw  tight. 

Bearing  scrapers.  Bearing  scrapers  must  be  kept  sharp.  A  good  India 
oil  stone  is  best  for  this.  Get  your  instructor  to  show  you  how  to  sharpen 
them. 


-Ring  Grooves 


CONNECTING  POO 
(BlAOS) 


Fig-.  163.  Cole  S  Connecting  rods  are  of  the  Yoked  Type.  The  inner  bearing  ia  non- 
adjustable.  When  the  play  is  too  great  these  are  replaced  with  new  ones.  The  Blade 
rod  is  adjustable.  Its  beatings  are  fitted  over  the  back  of  the  inner  bearing  which  is 
fastened  to  the  yoked  rod. 

JOB   50.     FITTING   OR   TAKING  UP   MAIN   ENGINE   BEARINGS. 

1.  Except  in  rare  cases  it  is  not  advisable  to  attempt  to  scrape  in 
bearings  with  the  engine  in  the  car  frame.  In  the  case  of  bearing  adjustment 
where  the  bearings  are  worn  loose,  but  are  otherwise  in  good  condition,  the 
work  is  ordinarily  done  with  the  engine  in  the  frame.  In  either  case  proceed 
as  follows. 

2.  Remove  bearing  caps  and  shaft. 

3.  Clean,  oil  and  reassemble. 

4.  Fit  rear  bearing  first,  by  the  adjustment  of  shims. 

a.  Remove  a  thin  one. 

b.  Assemble  and  test. 


150 


Automotive  Trade  Training 


C.     Continue  to  adjust  until  proper  tension  or  fit  is  obtained. 

5.  Remove  or  loosen  cap  on  rear  bearing. 

6.  Adjust  center  bearing. 

7.  Release  center  bearing  cap. 

8.  Adjust  front  bearing. 

9.  Reassemble  all  caps  using  a  coat  of  oil  on  the  bearings. 

10.     Have    each    bearing    when    finished,    inspected    and    final    assembly 
inspected  and  rated. 


Semoi'e  caps  to  adju^sT crank  Oeari/ii^s  and  connect/na  rods. 
I  JRemot'e  o//  ^p/a^h  p/afes  Defore 

J  I    anempT/ncf  to  rake  out  p/otons,.  ^^k 


Ma/n  o/ 1  pipe 

Connect/nf  rod^'        '|        O/i  pump  p/t^nt^er 
^3e  ~5ure  to  /ocH  nut's  w/t/?  i^/re  after  maH/ni^  adjuatment^. 


Fig.  164.     Adjusting  Rod  and  Main  Bearings   (Reo). 

JOB  51.     SCRAPING  MAIN  ENGINE  BEARINGS. 

1.  It  is  the  usual  practice,  in  case  bearings  are  in  such  condition  that  they 
need  scraping,  to  remove  the  engine  and  place  it  in  such  a  position  that  the 
work  of  scraping  in  the  bearings  is  made  accessible.  Where  a  minimum 
amount  of  work  is  required  the  engine  is  sometimes  left  in  the  car  frame.     The 


Fig.    165.      Laminated    Shims. 


Peel    off  a  layer  at  a   time   in  adjusting 
bearings. 


engine  should  be  removed  from  the  car  and  placed  in  an  advantageous  position, 
after  which  the  crank  case  should  be  removed  so  as  to  get  at  the  bearings  and 
shaft.     The  rods  should  also  be  removed. 

2.  Remove  the  bearing  caps  and  clean  free  of  all  oil. 

3.  Apply  a  thin  even  coat  of  bearing  blue  to  each  crank  shaft  bearing,  but 
not  to  the  crank  shaft  bearing  bushing. 

4.  Place  the  shaft  in  position  in  the  case. 

5.  Rotate  or  turn  the  shaft  three  or  four  times. 

6.  Remove  and  scrape  off  the  high  points  on  bearing  bushings. 


Functions  of  Engine  Parts 


151 


7.  Repeat  the  operation  until  all  bearings  are  properly  spotted  in.  At 
least  a  75  per  cent  bearing  surface  should  be  obtained,  otherwise  the  life  of  the 
bearing  will  be  greatly  shortened. 

8.  Extreme  care  and  considerable  time  are  required  on  this  job. 

9.  Metal  should  be  removed  by  very  careful  scraping.  Do  you  know  what 
.001"  is?  This  paper  is  .003"  thick.  It  might  be  written  3/1000.  In  scraping, 
inetal  should  not  be  removed  by  thousandths  of  inches  but  rather  by  one-eighth 
of  thousandths,  or  one-fourth  of  thousandths.     That  is,  to  remove  an  amount 


OSITION  or  WRENCH  WHEN  L  OCKING  SEARING,    j 
L    POSITION  OE  WRENCH  WHEN  ADJUSTING  SEAGING. 


Fife'.  106.     Adjusting  Main  Engine  Bearings.  Earlier  Models   (Reu). 

of  metal,  the  thickness  of  this  paper  would  require  from  25  to  50  cuts  of  the 
scraper. 

10.  Be  patient  and  observant  on  your  first  bearing  work.     All  speed  that 
is  possible  on  work  of  this  nature  will  come  to  you  later. 

11.  What    may    happen    if    too    much    metal    is    removed    from    the    front 
bearing? 

12.  What  may  happen  if  all  new  bearings  of  greater  than  original  thickness 
are  fitted? 

13.  Having   the   shaft   properly    fitted   or   aligned   in    the    crank   case,   the 
bearing  caps  may  be  fitted. 


152 


Automotive  Trade  Training 


14.  a.     Draw  the  end  ones  to  hold  the  shaft  in  place. 

b.  Work  the  center  bearing  to  a  fit. 

c.  Slack  the  nuts  on  the  center  bearing  a  trifle. 

d.  Fit  the  rear  main  bearing. 

e.  Fit  the  front  main  bearing. 

f.  Have  each  step  inspected  as  you  work. 

g.  See  that  all  oil  grooves  are  cared  for. 

15.  Have  final  assembly  carefully  oiled  and  keyed  with  cotter  keys. 

16.  Have  it  inspected  and  rated. 

JOB  52.     POLISHING  A  CRANK  SHAFT. 

In  use  a  crank  shaft  will  frequently  be  worn  so  that  grooves  and  ridges 
show,  or  are  noticeable  to  the  finger  tips  as  they  are  run  over  the  shaft  bearing. 
In  other  words,  it  is  scored.  The  score  marks  must  be  removed  by  one  method 
or  other  before  a  bearing  can  be  properly  fitted.  'Having  them  removed  and 
the  shaft  trued  up  it  may  be  polished  by  one  of  several  methods.  As  good  a 
method  as  any  is  the  following: 

1.  Wrap  a  piece  of  emery  cloth  a  little  narrower  than  the  bearing  around 
the  shaft  bearing. 


Pwten  Rings 


Oil  Hole* 


Space  for  Oiling 

Oil  Return  Holes 
Piston  Pin 


Oil  Return  Holes 


Connecting  Rod 


Connecting  Rod 
Bearing 


Dip  Pin 


Fig.  167. 


Overland   Piston   and   Rod  with  names 
of  parts. 


2. 
cloth. 

3. 
4. 


Take  a  light  rope  or  heavy  cord  and  give  a  number  of  turns  around  the 


Draw  this  back  and  forth  having  one  end  in  either  hand. 
Continue  this  until  the  shaft  has  a  good  bright  polish. 

5.  Care  must  be  used  to  see  that  emery  cloth  moves  from  side  to  side  as 
well  as  round  and  round. 

6.  Oil  may  be  used  on  the  cloth  if  desired,  but  this  is  likely  to  loosen 
some  of  the  grains  of  emery  from  the  cloth.  If  this  happens  the  shaft  may  be 
scratched.     In  any  event,  great  care  must  be  used  to  insure  a  good  polish. 


Functions  of  Engine  Parts  153 

JOB  53.     REMOVING  A  PISTON  PIN  OF  THE  CLAMP  TYPE. 

1.  Where  the  clamp  type  of  piston  pin  is  used,  the  pin  is  clamped  in  the 
rod  and  the  bushings  which  constitute  the  bearings  are  in  the  piston  pin  bosses. 

2.  Learn  how  the  piston  pin  is  secured, 

3.  Free  the  pin  by  loosening  the  clamp  fastener. 

4.  Remove  the  pin  by  driving  on  the  end  of  it  with  a  hammer  and  a  soft 
punch.  Either  hold  the  piston  on  the  knees  while  the  operator  is  seated  on 
the  bench,  or  set  the  piston  on  its  head  on  the  bench  and  drift  out  the  pin 
while  holding  the  piston  in  the  crook  of  the  arm.  To  press  out  a  piston 
pin  without  a  special  form  of  press  is  very  dangerous  as  the  piston  is  very 
often  pressed  out  of  round,  and  in  some  cases  is  injured  beyond  repair. 

5.  Note  the  position  of  the  bearing.  Is  this  arrangement  always  used? 
What  other  arrangement  might  be  used? 

JOB  53A.     REMOVING  A  PISTON  PIN  WHERE  THE  BUSHING  IS  IN 

THE  ROD. 

1.  Make  an  inspection  to  learn  the  method  of  securing  the  pin. 

2.  Loosen  the  pin  fastener  which  will  be  found  in  the  piston  pin  boss. 

3.  Remove  the  pin  by  driving  with  a  punch  having  the  piston  resting  on 
the  knees  of  the  operator  while  he  is  seated  on  a  bench,  or  set  the  piston  on 
the  head  on  the  bench  and  hold  with  the  arm  while  driving  against  the  pin.  To 
press  out  is  very  dangerous  as  the  piston  is  very  often  pressed  out  of  round. 

4.  Note  where  the  bearing  is.  Is  this  arrangement  always  used?  Could  it 
be  elsewhere? 

JOB  54.     REMOVING  PISTON  PIN  BUSHING  FROM  PISTON. 

1.  This  is  work  which  requires  good  judgment  on  the  part  of  the  operator, 
or  mechanic.     Unless  extreme  care  is  used  the  piston  may  be  ruined. 

2.  Secure  a  drift  of  a  slightly  smaller  diameter  than  the  outside  of  the 
bushing. 

3.  Hold  between  the  knees  while  seated  on  a  bench  and  drive  the  bushing 
into  the  piston. 

4.  In  replacing  a  bushing,  or  putting  in  a  new  one,  first  file  the  burr  from 
the  ends  on  a  taper  not  over  1/16"  long.  Start  true  and  drive  in,  using  a  wood 
block. 

5.  In  removing  a  bushing  from  a  rod  set  the  new  bushing  on  the  old  and 
press  the  old  one  out  and  the  new  one  in.     Be  careful  of  burrs. 

JOB  55.     FITTING  MAIN  ENGINE  OR  CRANK  SHAFT  BEARINGS  ON 

FORD  ENGINE. 

1.  After  the  engine  has  been  taken  out  of  the  car,  remove  the  crank  case. 
transmission  cover,  cylinder  head,  pistons,  connecting  rods,  and  transmission 
and  magneto  coils.  Take  off  the  three  babbitted  caps  and  clean  the  bearing 
surfaces  with  gasoline.  Apply  bearing  blue  to  the  crank  shaft  bearing  surfaces 
which  will  enable  you,  in  fitting  the  caps,  to  determine  whether  a  perfect 
bearing  surface  is  obtained. 

2.  Place  the  rear  cap  in  position  and  tighten  it  up  as  much  as  possible 
without  stripping  the  bolt  threads.  When  the  bearing  has  been  properly  fitted, 
the  crank  shaft  will  permit  moving  with  one  hand.  If  the  crank  shaft  cannot 
be  turned  with  one  hand,  the  contact  between  the  bearing  surfaces  is  evidently 
too  close  and  the  cap  requires  shimming  up.  one  or  two  brass  liners  usually 
being  sufficient.     In  case  the  crank  shaft  moves  too  easily  with  one  hand,  the 


154  Automotive  Trade  Training 

shims  should  be  removed  or  the  steel  surface  of  the  cap  filed  ofif,  permitting 
it  to  set  closer. 

3.  After  removing  the  cap,  observe  whether  the  blue  "spottings"  indicate 
a  full  bearing  the  length  of  the  cap.  If  "spottings"  do  not  show  a  true  bearing, 
the  babbitt  should  be  scraped  and  the  cap  refitted  until  the  proper  results  are 
obtained. 

4.  Lay  the  rear  cap  aside  and  proceed  to  adjust  the  center  bearing  in  the 
same  manner.  Repeat  the  operation  with  the  front  bearing,  with  the  other  twc> 
bearings  set  aside. 

5.  When  the  proper  adjustment  of  each  bearing  has  been  obtained,  clean 
the  babbitt  surface  carefully  and  place  a  little  lubricating  oil  on  the  bearings, 
also  on  the  crank  shaft;  then  draw  the  caps  up  as  closely  as  possible,  the 
necessary  shims,  of  course,  being  in  place.  Do  not  be  afraid  of  getting  the  cap 
bolts  too  tight,  as  the  shim  under  the  cap  and  the  oil  between  the  bearing 
surfaces  will  prevent  the  metal  being  drawn  into  too  close  contact.  If  oil  is 
not  put  on  the  bearing  surfaces,  the  babbitt  is  likely  to  cut  out  when  the  motor 
is  started  up  before  the  oil  in  the  crank  case  can  get  into  the  bearing.  In 
replacing  the  crank  case  and  transmission  cover  on  the  motor,  it  is  advisable 
to  use  a  new  set  of  felt  gaskets  to  prevent  oil  leaks, 

JOB  56.     REMOVING  ENGINE  FROM  FORD  CAR. . 

1.  Drain  the  water  out  of  the  radiator  and  disconnect  the  radiator  hose. 

2.  Disconnect  the  radiator  stay  rod  which  holds  it  to  the  dash. 

3.  Take  out  the  two  bolts  which  fasten  the  radiator  to  the  frame  and  take 
the  radiator  ofif. 

4.  Disconnect  the  dash  at  the  two  supporting  brackets  which  rest  on  the 
frame. 

5.  Loosen  the  steering  post  bracket  fastened  to  the  frame,  when  the  dash 
and  steering  gear  may  be  removed  as  one  assembly,  the  wires  first  having  been 
disconnected. 

6.  Take  out  the  bolts  holding  the  front  radius  rods  in  the  socket  under- 
neath the  crank  case. 

7.  Remove  the  four  bolts  at  the  universal  joint. 

8.  Remove  the  pans  on  either  side  of  the  cylinder  casting,  turn  ofif  the 
gasoline,  and  disconnect  the  feed  pipe  from  the  carburetor. 

9.  Disconnect  the  exhaust  manifold  from  the  exhaust  pipe  by  unscrewing 
the  large  brass  pack  nut. 

10.  Take  out  the  two  cap  screws  which  hold  the  crank  case  to  the  front 
frame. 

11.  Remove  the  bolts  which  hold  the  crank  case  arms  to  the  frame  at  the 
side.  Then  pass  a  rope  through  the  opening  between  the  two  middle  cylinders 
and  tie  it  in  a  loose  knot.  Through  the  rope  pass  a  "2x4",  or  a  stout  iron  pipe 
about  ten  feet  long,  and  let  a  man  hold  each  end.  Let  a  third  man  take  hold  of 
the  starting  crank  handle,  when  the  whole  power  plant  can  be  lifted  from  the 
car  to  the  work  bench  for  adjustment. 

» 

JOB  57.    ADJUSTING  CONNECTING  ROD  BEARINGS  ON  FORD 

ENGINE. 

1.  Drain  of?  the  oil. 

2.  Remove  the  plate  on  the  bottom  of  the  crank  case,  exposing  the 
connecting  rods. 

3.  Take  off  the  first  connecting  rod  cap  and  draw-file  the  ends  a  very  little 
at  a  time. 


Functions  of  Engine  Parts 


15^ 


4.  Replace  the  cap,  being  careful  to  see  that  punch  marks  correspond,  and 
tighten  the  bolts  until  it  fits  the  shaft  snugly. 

5.  Test  the  tightness  of  the  bearing  by  turning  the  engine  over  by  the 
starting  handle.  Experienced  mechanics  usually  determine  when  the  bearing 
is  properly  fitted  by  lightly  tapping  each  side  of  the  cap  with  a  hammer. 

6.  Loosen  the  bearing  and  proceed  to  fit  the  other  bearings  in  the  same 
manner. 

7.  After  each  bearing  has  been  properly  fitted  and  tested,  tighten  the  cap 
bolts  and  the  work  is  finished.  Remember  there  is  a  possibility  ot  getting  the 
bearings  too  tight,  and  under  such  conditions  the  babbitt  is  likely  to  cut  out 
quickly,  unless  precaution  is  taken  to  run  the  motor  slowly  at  the  start.  A 
good  plan  after  adjusting  the  bearings  is  to  jack  up  the  rear  wheels  and  let  the 
motor  run  slowly  for  about  two  hours,  keeping  it  well  supplied  with  water 
and  oil,  before  taking  it  out  on  the  road. 

JOB  58.     ADJUSTING  VALVE  TAPPETS. 

It  is  possible  to  set  the  tappets  on  the  modern  engine  up  so  close  as  to 
make  them  noiseless  in  practically  every  case.  This,  however,  is  not  good 
practice.  While  it  may  please  the  operator  and  owner  temporarily,  in  the  end 
it  is  certain  to  be  the  poorest  sort  of  economy.  It  is  generally  conceded  and 
known  that  the  heat  of  the  engine  is  sufficient  to  cause  the  valve  stems  to 
expand  quite  a  bit  over  their  length  when  cold.  The  result  is  that  when  they 
are  hot  the  cam  and  cam  shaft  will  have  to  bear  the  weight  of  the  explosion 
on  the  top  of  the  valve  since  it  will  not  quite  close  onto  its  seat.  This  load, 
which  is  Considerable,  may  also  result  in  the  springing  of  the  valve  stem.  It 
also  contributes  to  cut  and  worn  tappet  faces  and  cams.  Because  of  the  fact 
that  the  valve  does  not  quite  seat  there  is  always  a  loss  of  compression  past  it 
which  causes  the  face  of  it  to  be  burned  very  quickly.    Valves  were  designed 


To  adjust  the  clearance,  loosen 
'these  two  nuts,  and  screw  the  bal] 
stud  in  or  out  of  the  rocker  arm, 
using  a  screw  driver  through  the 
hole  in  the  upper  nut 


Pry  up  on  this 
end  of  the  rocker 
arm  before 
measuring 
clearance 


Fig.  168.    Adjusting  Valve  Clearance  on  Overhead  Valves   (National  Sextet). 


156 


Automotive  Trade  Training 


UJ§UI 

<o    ^ 

>WZ-I 

<E55 


UJqujo 
Ozm  ■ 

Z<     h 

<    Q52 
o:    _i3 

-If-lX 

O«C0Ui 


Functions  of  Engine  Parts 


157 


to  close  tightly  and  enough  clearance  between  the  tappets  and  the  lower  end 
of  the  valve  stem  must  be  allowed  that  the  expansion  of  the  stem  due  to  heat 
Avill  not  be  great  enough  to  overcome  the  allowance.  To  prevent  an  aggra- 
vating noise  set  them  all  alike.  Do  not  depend  on  feel  of  the  play,  but  rather 
upon    the   feeler   or   thickness    gauge.     Allow   .004"    to    .006"   clearance. 


Of/  nere 
ya/re  push  rod  end 
Ct^/inden. 


fd/ye 
EjrtJdusr 
ra/ye  ^pr/dif 
ra/ye 

E^/7du^r  i^af/e 
j/fter  ddji/3r//7^ 

acrew 

E^hau^r  m/y'e 
//fter  fack  nt/t 

E^tidust 
/dfi^e  //rrer 


Cdm  shaft 


P^/ye  /eyer  fa/crt/m  i>a/t 

.004''Md^/mu/r7i 
c/earance 

Inlet  ya/ye 
<3pr/nc^ 


Inlet  yd/ye 
Inter  /at re  otem  <:^u/de' 

Va//e  pu^t?  rod 

^^"^E^ttdust  ra/ye  ^fem  efu/diS 
.OO^^'^Majr/mum  c/edrddce 

Hdjust  inlet  yat/epu<5h  rod  here 

/IdjUssrment  toc/c  nut 

In  let  mtre  //fter- 

Ka/Ke  t/ffer  efuide 


ta/re  t/fter  rotter  p/n 
Fat  ye  t/fter  rotter 


Fig.  170.     Reo  F  Head  Valve  Operating  Mechanism. 

1.  To  adjust  tappets  the  engine  should  be  put  in  the  same  position  as  for 
grinding  valves,  that  is,  on  compression  stroke  for  the  cylinder  to  which  the 
tappets   belong. 


158  Automotive  Trade  Training 

2.  With  a  thickness  or  feeler  gauge  test  the  clearance  between  the  top  of 
the  tappet  adjusting  screw  and  the  bottom  of  the  valve  stem. 

3.  The  amount  of  clearance  should  be  adjusted  to  .004"  for  intake  and  .006" 
for  exhaust  or  that  recommended  by  the  riianufacturer  of  the  particular  engine 
being  repaired. 

4.  Why  is  this  amount  of  clearance  not  the  same  in  all  cases? 

5.  In  the  case  of  tappets  not  adjustable  the  valve  stem  will  need  to  be 
filed  if  it  is  too  close. 

JOB  59.     METHODS  OF  REMOVING  VALVES. 

As  the  student  is  already  aware,  the  position  of  the  valves  in  the  engine  is 
not  always  the  same.  Neither  is  the  method  of  securing  them  in  position  just 
the  same  in  every  case.  The  usual  method  of  holding  the  spring  in  place  is  to 
put  a  cupped  washer  under  the  spring,  and  under  the  washer  either  a  horse 
shoe  retainer  or  a  pin.  In  rare  cases  the  valve  adjustment  is  on  the  lower  end 
of  the  valve  stem  and  the  spring  and  washer  are  thus  retained. 

1.  Learn  the  best  method  of  getting  at  the  valves. 

a.  Remove  valve  covers. 

b.  Remove  port  plugs. 

c.  Remove  head. 

2.  Having  valves  accessible,  next  proceed  to  remove  them. 

a.  Fit  on  a  valve  lifter. 

b.  Release  tension  on  pin  or  retainer  by  compressing  spring. 

c.  Release  spring. 

d.  Remove  valve  lifter. 

e.  Remove  valve. 

f.  Inspect  for  marking.     If  not  marked  be  certain  to  do  so  at  once, 
otherwise  the  valves  will  become  mixed  and  much  trouble  will  result. 

3.  In  this  manner  remove  all  valves. 

JOB  60.     CLEANING  VALVES. 

After  the  valves  have  been  removed  from  the  engine,  the  next  step  is  to 
clean  them  free  of  all  carbon  accumulations.  At  times,  too.  there  will  be  rust 
on  the  stem,  particularly  where  the  oiling  system  has  failed.  Several  methods 
are  in  use  for  cleaning  them. 

1.  Scrape  the  carbon  off  with  a  knife. 

2.  Polish  the  head  and  stem  with  fine  emery  cloth.     This  may  be  done. 

a.  Bore  a  hole  in  a  board  that  will  be  a  snug  fit  for  the  valve  stem. 
Hold  the  board  in  a  vise  and  polish  by  running  a  strip  of  emery 
around  the  valve  and  the  stem. 

b.  Hold  the  valve  in  a  portable  drill  or  breast  drill  chuck.  Polish 
while  turning  by  holding  the  emery  cloth  against  the  valve. 

c.  Hold  the  valve  in  the  drill  press  or  lathe  chuck  and  polish. 

d.  Polish  by  hand. 

3.  Kerosene  is  often  of  aid  in  removing  carbon  deposits  and  gummed  oil. 

JOB  61.     GRINDING  VALVES. 

The  following  directions  apply  equally  well  to  all  types  of  cars,  except- 
ing to  those  of  the  removable  valve  cage  construction.  In  that  case  the 
cages  are  removed  and  the  end  of  the  valve  stem  is  gripped  in  the  vise,  after 
which  the  cage  is  rotated  on  the  valve  in  much  the  same  manner  as  the 
following  process  where  the  valve  is  rotated. 

1.     Secure  a  valve  grinding  tool  and  some  compound. 


Functions  of  Engine  Parts 


159 


2.  Place  a  little  valve  grinding  compound  on  the  valve  face,  using  the 
finger  to   distribute  it. 

3.  Place  the  valve  in  the  engine  until  it  rests  on  the  valve  seat. 

4.  Have  the  piston  for  cylinder  No.  1  on  T.  D.  C.  compression  stroke. 
This  may  be  obtained  by  turning  the  engine  by  hand  until  both  the  exhaust  and 
intake  valves  are  seen  to  work  one  foUow^ing  the  other  closely  and  then 
one-half  turn  farther. 


Fig.   171.     Grinding  Valves  Using  a   Screw  Driver   as   a  valve  grinding  tool    (Overland). 

5.  With  the  grinding  tool  turn  the  valve  about  three-fourths  turn  around 
and  then  reverse,  at  the  same  time  applying  a  light  even  pressure. 

6.  Start  with  a  coarse  or  medium  compound  depending  on  the  condition 
of  the  valves. 

7.  Continue  until  all  pits  are  removed,  then  finish  and  polish  with  fine 
compound. 

8.  Considerable  patience  is  required  in  this  work.  A  light  coil  spring 
placed  under  the  valve  head  will  facilitate  its  removal.  Also  help  to  speed  up 
the  grinding  as  it  can  be  depended  on  to  raise  the  valve  and  let  it  be  reseated 
quickly  at  another  point. 

9.  Have  the  job  inspected  as  you 'progress  and  when  the  first  valve  is 
finished. 


Valve  Lifting  Tod 


Valve  Spring 


Valve  Spring  Seal 


Valve  Seal  P« 


Valve  Stem 


Fig.   172.     Lifting   Valve   Springs    (Ford, 


160 


Automotive  Trade  Training 


10.  When  all  are  finished  the  work  should  be  rated. 

11.  When  reassembled  it  will  be  found  necessary  to  test  all  valve  tappets 
and  have  them  adjusted  when  necessary. 

JOB  62.     RESEATING  VALVES. 

In  cases  where  the  valves  have  been  ground  a  number  of  times  and  show 
a  considerable  shoulder  it  will  be  necessary  to  reseat  them  to  secure  a  good 
job,  otherwise  the  seating  face  grows  too  wide  and  the  valve  is  also  liable  to 
hang  on  the  shoulder  in  its  face.  A  number  of  good  sets  of  tools  are  on  the 
market  which  may  be  used  for  this  work.  The  sets  consist  of  a  tool  used  for 
refacing  the  valve  itself  and  a  separate  tool  which  is  used  to  ream  out  the  valve 


Fig.    173.     Lifting   Valve    Springs    (Overland). 


Fig.  174.     Grinding  Valves. 


seat.     In  some  cases  the  valve  port  wall  is  reamed  out  to  permit  of  a  so-called 
hair  line  contact  of  the  valve  on  its  seat. 

1.  Re-face  the  valve  first  by  carefully  setting  it  up  in  the  tool,  taking  just 
a  light  cut  from  its  face. 

2.  Reseat   the  valve   by   using  the   reaming  cutter  properly   fitted   to   the 
cylinder  casting  in  the  valve  port. 

3.  In  either  case  use  a  firm  even  pressure,  and  do  not  remove  any  more 
metal  than  is  necessary  to  secure  a  true  seat  or  face. 

4.  Grind  as  in  Job  61  to  finish. 


JOB 


TIMING  ENGINES. 


The  student  having  studied  the  previous  instruction  given  in  this  chapter 
on  valve  timing  will  be  in  a  position  to  understand  the  actual  operation  as 
explained  below.  These  instructions  will  apply  in  a  general  way  to  any  job 
of  valve  timing.  A  number  of  charts  representative  of  general  practice  are 
given. 

1.  Ordinarily  timing  gears,  whether  chain  driven  or  gear  driven,  are 
marked,  but  this  is  not  always  the  case.  After  the  timing  gears  have  been 
exposed,  which  means  removing  the  plate  covering  them,  the  next  step  is  to 
inspect  the  gears  for  timing  marks. 


Functions  of  Engine  Parts 


161 


2.     If  no  marks  are  present,  the  mechanic  will  do  well  to  place  some  after 
first  setting  the  engine  in  timing  position. 

I 

S 

•4  A 


3.  The  parts  may  now  be  disassembled  to  allow  for  any  replacement  and 
repairs. 

4.  When  replacing  the  timing  gears  the  cam  shaft  must  be  replaced  in 
proper  position  as  well  as  the  crank  shaft  and  pistons,  after  which  the  gears 
may  be  replaced. 


162 


Automotive  Trade  Training 


5.  Where  new  gears  are  to  be  placed  in  the  engine  it  is  possible  to 
transfer  the  marks  from  the  old.  However,  in  such  case  the  engine  should  be 
timed  with  complete  exactness  to  check  up  the  setting  of  the  gears  as  there  is 
a4ways  a  possibility  of  making  a  mistake  in  transferring  marks. 

rLyyyHC£L  t/at/ns  mafks. 


ALL   -^  CrUA/D£/f    CONT/NCNTAL    MOTO/fS 

HA^^B:   the  rOLLOkV/A/G    r/RJNG   OffDE/f 

AND   ROTATE  CLOC^I/V/SC,  y^El^£D  FROM  FRONT. 
Fig^  176.     Continental  4  Engine   Timing, 

6.  In  all  cases  of  engine  timing  the  real  proof  of  exactness  is  not  the 
marks  on  the  gears,  but  the  position  of  the  crank  shaft  and  piston  assembly 
in  relation  to  the  cam  shaft,  valve  tappets  and  valves.  This  proper  relation 
has  been  explained  at  an  earlier  point  in  the  chapter. 

7,  Never  attempt  to  check  up  the  engine  timing  until  the  valve  tappets 
have  been  properly  set.     Too  great  a  clearance  in  the  tappet  adjustment  will 


Functions  of  Engine  Parts. 

Marks  on  Gear  Te«(h 


163 


Can  SIwHGma 


Crank  SImH  C«w 


Fig.  177.     Showing  Method  of  Marking  Timing  Gears. 


5Cr0ffC  RCtlOVitIG  Any 6CA^5,  TURtiCRAriK^iMArT  TO  PO^lTlOn  5H0Wn,(nilCK 

FuncnnAKK5'As,'5'0PP05iTc)ifi  WHICH  posmon  thc  't  inur  v^lvc  /3  JU6r  f^cAor 

TO  0PCti(BAO<LA5H ALL  TAKCfl UP) 

IF GCnCHATOK  GCAR  l5  TO  BC RCMOVCD.  riARK  CAtf  SCAR  S  6ChCRAT0R  GCAR  IN 
SUCHArtAlirrCRTHAT  THCYCAtiBCRCA^SCflBLCO  /N THC  5AflC P05mon 

ir  OMLY  CAMSHAFT  OR  CRAHKiHAPT  GCAR  /5  TO  BC  RCMOVCD,  5C  ^URC  THAT 
GChCRA  7QR  GCAR  /J  NOT  D/5TUR6CD  BCrORC  RCA6SCn6urr6 

IP  A  new  CAM  OR  CRAnn5HAPT  GCAR'  l6  TO  BC  PUT  in,  MARK.  A^  AT 'A' OR '5' 
THC  PKOPCR  TOOTH  OR  TOOTH  5PACC (mQTC  RCLATivC  POSlTlOH  OF  PITICK  PUtlCH 
701  OF KCYWAY)5AHC  Ab  OLD  GCAR 

new  GCAR6  WILL  cone  UhfTARKCD. 


UPPCROCAOCChTCR 
J ^ 


IJS(X)lHLCT     uj 


opcny'  LATc 


U{\ 


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LATC         «o| 


y303(HjlHLCT 
CL05C3  LATC 
\400(i^)CAHAU3T 

iorcn^  carly 


LOW€R  OCAO  CCHTCA 


Fig.  178.    Setting  Timing  Gears. 


164 


Automotive  Trade  Training 


make  a  very  decided  difference  in  the  point  of  piston  travel  at  which  the  valve 
will  open.  Neglect  of  this  point  may  cause  serious  trouble  and  even  retiming 
when  it  is  not  necessary. 

8.     As  a  rule,  the  timing  of  an  engine  needs  little  thought  as  it  is  fixed  in 
such  a  manner  that  there  is  no  chance  of  it  failing.     However,  too  much  care 


MOTE.  DISTRIBUTOR  AND  SPARK  LEVERS 
TO  BE  SET  nAi.  ADVAMCE  WHEM  THIS 
POIMT  IS  AT  TOP  POSITIOn. 


MARK  on  WHEEL 


?^m^ 


^lOn  OF  ROTATlOn 
Fig.  179.     Nash   Flywheel  Timing  Chart. 

cannot   be    exercised   in    overhauling    an    engine    to    see    that    it    is   properly 
maintained. 

JOB  64.     SILENT  CHAIN  CARE. 

The  chain-driven  cam  shaft  and  timing  gears  are  used  to  a  very  consid- 
erable extent.  The  silent  chain  is  also  used  to  drive  the  generator,  pump, 
magneto,  etc.  In  some  cases  it  is  used  to  transmit  the  power  from  the  starting 
motor  to  the  engine  shaft.  In  service  the  chain  will  be  stretched  and  should 
be  adjusted  at  each  5000  miles  to  compensate  for  the  wear.  In  most  cases  the 
play  or  shake  in  the  chain  should  be  about  >4"  at  the  point  shown  in  Fig.  180. 
This  is  standard  practice.  A  chain  either  too  tight  or  too  loose  is  prone  to  be 
noisy.  The  one  too  tight  is  also  subject  to  breakage  and  causes  undue  wear 
on  the  bearings.  The  one  too  loose  is  likely  to  jump  from  the  gears  and  thus 
do  great  damage, 


Functions  of  Engine  Parts 


165 


There  are  several  methods  of  tightening  chains.  In  many  cases  where  the 
generator  is  chain-driven,  the  chain  is  tightened  or  loosened  by  manipulating 
the  eccentric  block  through  which  the  end  of  the  generator  shaft  enters  the 
chain  case.  In  other  cases  an  idler  gear  is  utilized.  Where  great  wear  and 
stretch  are  apparent  it  may  be  necessary  to  remove  one  or  two  links.  In  cases 
where  two  links  may  be  removed  at  one  time  the  chain  may  be  connected 
without  any  trouble.  Where  only  one  link  may  be  removed  the  two  ends  of 
the  chain   will  not   fit   together  and  permit   alignment.     To   correct   this   fault 


WASHER 


ROCKER  PIN 


SEAT  PIN 


When  the  chain  is  properly 
adjusted  there  should 
be  about  Yi"  shake  back 
and  forth 


Fig.   180.     Silent   Chain   Adjustment  and   Assembly    (National   Sextet). 


two  links  are  removed  and  a  hunting  link  is  substituted.  This  link  will  align 
the  ends  of  the  chain  properly. 

OPENING  CHAIN.  Two  methods  are  in  use  in  this  work.  Some  chains 
are  provided  with  a  special  link  which  is  fastened  in  place  with  cotter  keys,  or 
wire,  or  other  special  fastener.  In  some  cases  no  special  link  is  provided  and 
the  ends  of  the  seat  pin,  Fig.  180,  are  riveted  over  the  washer  thus  inclosing 
and  retaining  the  rocker  pin  which  is  made  shorter  than  the  seat  pin.  When 
the  chain  is  riveted  together  at  each  pin  it  will  be  necessary  to  file  off  the 
riveted  end  of  the  seat  pin  to  remove  it.  When  replacing  seat  pins,  new  pins 
should  be  used  to  permit  of  making  a  workmanlike  and  safe  job.  It  is  also 
well  for  the  student  to  learn  the  direction  of  rotation  of  the  silent  chain. 
Arrow  heads  are  sometimes  stamped  on  the  chain  links  to  indicate  this.  As 
shown  in  Fig.  180,  the  seat  pin  should  travel  ahead. 

LUBRICATION.  In  practically  every  case  the  chain  is  housed  in  the 
timing  gear  case  and  lubricated  by  the  engine  oiling  system.     This  is  splash 


166 


Automotive  Trade  Training 


in  some  cases,  in  others  the  chain  dips  into  a  well  of  oil,  and  in  others  a  stream 
of  oil  is  fed  onto  the  chain  as  it  runs. 

JOB  65.     REMOVING  A  CYLINDER  HEAD. 

A  large  percentage  of  cars  use  engines  fitted  with  removable  heads.     This 
in  itself  is  a  most   splendid  feature  when  it   comes   to   carbon   removal,  valve 


Fig.  181.     ritjmoviiiy  a  Cylinder  head    (Allen). 

care,  etc.  On  the  other  hand,  a  cylinder  head  carelessly  handled  may  be  the 
source  of  much  trouble.  The  act  of  removing  the  head  is  one  requiring  good 
judgment  on  the  part  of  the  mechanic.  The  following  outline  of  steps  for  this 
work  will  help  the  student: 

1.  Drain  the  radiator. 

2.  Remove  all  hose  connections  which  will  prevent  the  head  being  lifted 
free. 

3.     Loosen   all   other   parts   such   as  vacuum   tank   and   horn  which   may   be 
attached  in  any  way  to  the  head. 

4.  Remove  all  the  nuts  or  studs  holding  the  head  in  position. 

5.  Test  head  with  the  hands  to  see  if  it  is  loose. 

6.  Failing  to  be  able  to  loosen  the  head  with  the  hands  the  engine. may  be 
cranked  over.  The  compression  will  break  the  head  loose.  When  using  this 
method  to  loosen  the  head  it  is  well  to  have  a  nut  or  stud  in  place  at  each  end 
to  prevent  the  head  being  forced  all  the  way  off. 

7.  When  the  head  is  loose,  the  next  step  is  to  get  it  raised  far  enough  to 
permit  the  workman  lifting  it  by  placing  his  fingers  between  the  cylinder  head 


Functions  of  Engine  Parts 


167 


and  the  block.  This  may  be  accomplished  by  the  judicious  use  of  a  screw- 
driver. The  gasket  will  be  harmed  by  the  screw  driver  if  the  point  is  jabbed 
into  it. 

8.  With  the  head  blocked  up  to  permit  the  workman  to  grasp  it,  the  usual 
practice  is  to  stand  astride  of  the  engine  while  raising  the  head  up  and  off 
the  studs. 

9.  Next  raise  the  gasket  from  the  block,  using  extreme  care  that  it  is  not 
twisted,  kinked,  or  otherwise  harmed.  Put  it  in  a  place  where  it  will  be  safe 
from  any  abuse. 

JOB  66.     REPLACING  A  CYLINDER  HEAD. 

The  work  of  replacing  a  cylinder  head  in  such  a  manner  that  no  parts  will 
be  damaged,  and  yet  that  all  joints  may  be  perfectly  sealed,  is  a  difficult  one 
for  the  inexperienced.     The  following  suggestions  will  be  of  help: 


COUNTEP   BORED 


Pig.  182.     Method  of  counterboring  to   relieve  tight  point  on  cylinder  head  assembly. 

1.  Clean    all    carbon    deposits,    rust,    grease,    or    dirt    from    the    machined 
surfaces  of  the  head  and  block. 

2.  Test  with  a  straight  edge  such  as  a  steel  rule  or  square  to  see  that  the 
two  surfaces  are  true. 

3.  Remove  any  and  all  burrs  around  the  edges  and  around  the  studs  such 


Fig.  183,    Cadillac,  right  hand  cylinder  head  removed. 


168  Automotive  Trade  Training 

as  those  shown  in  Fig.  182,  Where  the  burr  is  around  the  stud,  the  stud  should 
be  removed  and  the  hole  countersunk.  Burrs  raised  around  the  edges  should 
be  removed  with  a  flat  file.  If  the  gasket  has  been  s-hellaced  on,  the  old  shellac 
will  have  to  be  scraped  off.  Make  certain  that  there  is  nothing  at  any  point 
which  will  prevent  the  head  from  coming  down  evenly. 

4.  If  the  old  gasket  is  badly  worn  and  in  poor  condition  the  best  and 
safest  plan  is  to  replace  it.  A  gasket  well  cared  for  should  last  for  five  or  six 
head  removals. 

5.  Coat  the  gasket  both  sides  with  cup  grease;  also  place  a  light  coat  of 
cop  grease  on  the  machined  surfaces  of  the  head  and  block. 

6.  Place  the  head  in  position  making  certain  that  there  are  no  tools,  studs, 
nuts  or  other  objects  in  the  cylinders. 

7.  Place  in  all  studs,  or  if  they  are  already  in  the  block,  place  on  all  nuts, 
running  them  down  until  all  are  ready  to  seat  on  the  head.  With  a  socket 
wrench  which  fits  the  heads  or  nuts  properly,  draw  each  stud  in  turn  until  all 
are  exerting  a  slight  pressure  on  the  head.  Continue  this  operation  until  by 
the  most  careful  work  all  studs  have  been  drawn  tight.  To  draw  on  one  stud 
to  the  neglect  and  exclusion  of  others  will  most  certainly  cause  trouble. 

8.  A  stud  is  tight  when,  a  decided  pressure  is  brought  to  bear  on  the  head. 
By  using  a  large  wrench,  or  long  handled  one,  it  may  be  drawn  tighter  than  is 
actually  needed.  This  may  result  in  the  cylinder  block  being  distorted  in  some 
cases  and  this  distortion  may  be  so  bad  as  to  cause  leaky  valves.  In  other 
cases  the  stud  may  be  pulled  up  in  such  a  manner  that  the  metal  immediately 
around  the  stud  is  raised  and  instead  of  the  leak  being  stopped  it  is  made  worse. 

9.  In  cases  where  undue  pressure  or  force  is  used  the  studs  are  frequently 
broken  off  in  the  block.  This  means  the  head  must  be  removed  and  the 
broken  stud  taken  out. 

10.  After  the  engine  has  been  run  long  enough  to  warm  it  up  thoroughly 
the  next  step  is  to  go  over  all  studs  once  more  to  give  each  one  a  final  turn. 
This  is  usually  possible  due  to  the  fact  that  the  heat  has  expanded  the  stud  a 
bit,  and  also  to  the  fact  that  the  heat  will  run  out  some  of  the  cup  grease. 

JOB    67.     SHELLACING   A   CYLINDER   HEAD    TO    PREVENT 
COMPRESSION  LEAKS. 

It  frequently  happens  that  due  to  an  old  gasket,  or  head,  which  is  in  bad 
condition,  it  is  difficult  to  make  the  cylinder  head  gasket  joint  leak-p'-oof.  In 
making  a  test  to  learn  if  the  gasket  is  permitting  leaks,  proceed  as  follows: 

1.  Remove  head  and  gasket. 

2.  Clean  free  of  all  grease. 

3.  Coat  the  gasket  each  side  with  white  lead. 

4.  Replace  the  gasket  and  head. 

5.  Run  the  engine,  under  load  if  possible. 

6.  Remove  the  head  again.  Any  points  where  the  white  lead  shows  black 
streaks  are  points  at  which  the  compressed  gasses  have  been  leaking  from  the 
cylinders. 

7.  Clean  the  gasket  of  all  the  lead,  grease  and  oil. 

8.  Coat  the  gasket  and  machined  surfaces  of  the  head  and  block  with  a 
thin  coat  of  rim  and  gasket  shellac. 

9.  Allow  the  shellac  to  dry  until  it  is  tacky  to  the  touch.  Apply  the  head 
in  the  usual  manner. 

10.  In  cases  where  cylinder  head  gaskets  develop  serious  leaks  between 
the  cylinders,  it  is  sometimes  advisable  to  shellac  in  a  strip  of  paper  on  the  part 
of  the  gasket  indicated  by  the  arrow  in  Fig.  184.  This  will  prevent  the  com- 
pression starting  a  leak  which  will  later  develop  into  serious  trouble. 


Functions  of  Engine  Parts 


169 


FOULED  CONDITION  OF  CASKET  AT 
THIS  POINT  INDICATES  LEAKAGE 
BETWEEN   CYLINDERS 


r 


Fig.  1S4.     Hudson  block  with  liead   removed. 


JOB  68.     FITTING  NEW  PISTON  RINGS. 

To  properly  seal  the  walls  between  the  piston  and  cylinder  the  piston  ring 
must  be  most  carefully  fitted.  Three  forms  of  clearances  must  be  figured  by 
the  mechanic.  The  side  and  back  clearances  are  illustrated  in  Fig.  186.  The  end 
clearance  is  illustrated  in  Fig.  187.  These  clearances  are  figured  always  in 
thousandths  of  an  inch.  A  feeler  gauge  is  absolutely  necessary  to  a  good  piece 
of  work.  The  workman  who  attempts  jobs  of  this  nature  without  the  proper 
measuring  devices,  depending  on  his  eyesight  alone,  will  never  earn  the  title 
ot  mechanic.  The  person  with  a  trained  eye  may  tell  the  difference  between 
.002"  and  .004",  but  the  average  workman  can  not  say  with  any  degree  of 
accuracy  whether  a  certain  space  is  .010"  or  .030".  In  fitting  new  rings  proceed 
as  follows: 

1.  Drain  the  radiator,  remove  the  cylinder  head,  and  do  such  other 
preliminary  work  as  may  be  necessary  to   remove   the  piston.     Make   certain 

that  the  piston  rod  and  cap  are 
properly  marked  so  as  to  insure 
their  proper  return  to  the  orig- 
inal cylinder.  Do  not  lose  any 
shims  from  the  bearing. 

2.  Remove  the  rings.  If 
difBcult  to  remove,  use  three  old 
hack  saw  blades  or  strips  of 
sheet  metal  to  slip  under  the 
rings  and  hold  them  expanded 
while  slipped  over  the  ring 
grooves.     Fig.    185. 

3.  If  the  old  rings  are  to  be 
used  again  they  should  be  main- 
tained in  order  that  the  top  one 
may    be     returned    to    the    top 


Fig.  185.    Using  skids  to  remove  piston  rings. 


groove,  and  so  on. 

4.     To  learn  if  the  old  rings  are  fit  to  be  used  again,  first  roll  them  in  the 
grooves  of  the  piston  to  note  side  clearance.     This  should  be  just  enough  to 


170 


Automotive  Trade  Training 


SIDE  CLEARANCE 


Fig-.  186.     Piston   King  Clearance. 

allow  them  to  slide  without  gripping  the  sides  of  the  groove.     In  other  words, 
there  should  be  no  appreciable  play  up  and  down  in  the  groove.     Fig.  190. 

5.  Test  the  old  ring  in  the  cylinder  to  learn  if  there  is  an  excessive  amount 
of  end  clearance.  If  this  is  .003"  or  more  for  each  inch  of  diameter  of  the 
cylinder,  the  ring  should  be  replaced  with  a  new  one.  For  instance,  if  the 
thickness  gauge  shows  this  end  clearance  to  be  more  than  .009"  for  a  3"  piston 
the  clearance  is  too  great  and  the  ring  needs  to  be  replaced. 


Fig.  187.     Piston    Kiny  Clearance. 


6.  In  fitting  new  rings  the  first  step  is  to  secure  the  proper  size  of  ring 
from  the  supply  house  or  dealer.  Usually  these  are  a  bit  large  and  to  fit  them 
the  ends  must  be  filed  to  permit  of  the  proper  clearance. 

7.  Place  the  new  ring  in  the  cylinder.  File  ofT  the  end  until  it  will  just 
lay  even  with  no  clearance. 

8.  Note  whether  the  ring  lies  in  close  contact  with  the  cylinder  walls  at  all 
points,  or  whether,  with  a  light  beneath  it,  it  shows  away  from  the  walls  at 
certain  points.  If  it  does  stand  away  a  considerable  amount  at  any  one  point,  it 
may  be  necessary  to  pien  it  at  that  point  to  make  it  conform  more  nearly  to  the 
cylinder!  This  is  a  job  requiring  patience  or  the  ring  will  be  broken.  Rings 
are  cast  grey  iron.     Fig.  188. 

9.  With  the  ring  conforming  pretty  well  to  the  cylinder,  it  may  1)e  placed 
on  an  old  piston  or  on  a  dummy  piston  and  lapped  to  a  still  better  fit.  To  do 
this,  place  a  bit  of  fine  valve  grinding  compound  on  the  ring's  outer  surface. 
Moving  the  dummy  piston  and  ring  up  and  down  in  the  cylinder  while  giving 
it  a  circular  motion  will  quickly  fit  the  ring  to  the  cylinder  wall.  Do  not  use 
the  coarse  grinding  compound  in  this  lapping  operation.     Clean  the  ring  and 


Functions  of  Engine  Parts 

Openfn^ 


171 


Fig.  ISS.     Piston  Ring  in  need  of  piening  to  make  it  fit  up  to  the  cylinder  wall. 

the  cylinder  most  carefully  after  the  operation  is  completed. 

10.  Put  the  ring  in  position  in  the  cylinder  and  make  a  test  with  the 
thickness  gauge  for  end  clearance.  The  top  ring  should  have  a  clearance  of 
.0015"  to  .003"  per  inch  diameter  of  the  cylinder.  The  lower  rings,  not  being 
subjected  to  quite  as  much  heat  as  the  top  one,  may  be  a  bit  closer.  File  until 
proper  clearance  is  obtained,  remembering  that  in  the  case  of  the  bevel  cut  lap 
when  the  clearance  shows  on  the  gauge  as  .004",  it  is  in  fact  .006",  or  one  and 


Fig.   isn.     losing   a   thickness   gauge   in   fitting   a   piston   ring.    Measuring  end   clearance. 

one-half  times  as  great  as  the  thickness  gauge  shows.  This  fact  is  due  to  the 
angularity  of  the  lap.  A  step  cut  ring  will  show  the  actual  clearance  when 
measured. 

11.  The  next  point  is  to  test  the  side  clearance  and  fit  the  ring  into  the 
piston  groove.  In  this  work  the  ring  is  rolled  around  the  groove  as  indicated 
in  Fig.  190.  Starting  at  diflFerent  positions  make  at  least  three  tests  to  see  if 
the  ring  appears  to  be  the  same  width  at  each  point.     If  too  wide,  the  width  is 


173 


Automotive  Trade  Training 


reduced  by  placing  a  sheet  of  medium  or  fine  emery  cloth  on  a  plate  glass 
surface  or  on  a  surface  plate.  A  perfectly  true  bench  top  or  board  may  be  used 
in  case  nothing  better  is  at  hand.  Grasping  the  ring  under  the  finger  tips  the 
mechanic  gives  it  a  rotating  motion  on  the  emery  cloth,  testing  each  little  while 
to  see  how  it  is  being  reduced.  As  quickly  as  one  point  shows  signs  of  fitting, 
that  point  must  be  protected  from  further  cutting  as  the  work  proceeds.  When 
all  points  are  just  entering  the  groove,  extreme  care  must  be  used  so  as  to 
finish  up  the  work  in  such  a  manner  that  the  ring  will  just  slide  around  the 
groove  in  the  piston  when  it  is  put  in  position  on  the  piston.  It  should  have 
just  a  little  tacky  or  sticky  resistance  to  sliding.  The  piston  expands  more 
than  the  ring  when  heated  and  will  clear  it  nicely. 

12.  The  final  test  for  the  ring  is  to  learn  if  the  ring  is  a  bit  thinner  than 
the  groove  is  deep.  This  is  the  back  clearance  and  should  be  .002"  per  inch 
diameter  of  the  piston.  Too  great  a  clearance  allows  the  carbon  to  collect 
back  of  the  ring  and  this  in  turn  may  cause  rings  to  stick. 

13.  Carefully  fitted  rings  will  do  more  to  repay  for  the  expense  of  making 
the  job  right  than  perhaps  any  one  other  thing.  They  mean  more  power,  more 
mileage,  less  oil  consumption,  less  fuel  consumption,  less  carbon  accumulation, 
less  bearing  trouble  and  fewer  repair  bills. 


Fig.    190.     Pitting    Piston    King   to    Groove. 

JOB  69.     FITTING  NEW  PISTONS. 

There  are  a  number  of  causes  which  contribute  to  such  wear,  normal,  or 
abnormal,  which  make  necessary  the  fitting  of  new  pistons.  If  no  abnormal 
conditions  are  present  the  engine  will  give  many  miles  of  service  without  the 
pistons  or  cylinders  wearing  to  such  a  degree  that  the  old  pistons  must  be 
discarded  and  new  ones  installed.  However,  even  in  normal  service  there  is 
some  wear  on  the  piston  and  the  cylinder  tends  always  to  wear  out  of  round  and 
egg  shaped.  Under  abnormal  conditions  as  when  the  engine  overheats  or  is 
run  without  oil,  or  when  the  cylinders  and  pistons  score  for  any  reason,  it  is 
almost  certain  to  produce  enough  damage  that  the  pistons  at  least  will  have  to 
be  replaced. 

In  cases  where  the  cylinders  are  scored  badly  as  would  be  the  case  in  piston 
pin  scores,  the  cylinder  block  would  have  to  be  repaired  or  replaced.  In  the 
minor  cases  of  scoring,  and  to  correct  the  cylinder  worn  oval  due  to  long- 
service,  the  following  method  may  be  used  to  fit  new  pistons.  If  the  cylinder 
is  worn  from  .010"  to  .015"  out  of  round  the  job  is  one  requiring  reboring  and 
the  following  method  would  not  give  a  mechanically  correct  job: 

1.     Tear  down  the  engine   and   get  the  cylinder  block  in   such   condition 


Functions  of  Engine  Parts  173 

cither  in  the  frame  of  the  car,  or  on  the  bench,  or  stand,  that  the  work  may 
proceed  without  hindrance. 

2.  Measure  up  the  cylinders  to  learn  the  size  of  the  new  pistons  to  be 
ordered.  In  some  cases  it  is  advisable  to  put  the  cylinders  in  good  condition 
before  ordering  the  new  pistons. 

3.  To  put  the  cylinder  in  good  condition  use  an  old  piston  for  a  lapping 
tool.  Mount  a  handle  on  the  wrist  pin  to  use  in  working  the  piston  up  and  down 
and  round  and  round  as  the  work  is  in  progress.  This  handle  may  be  made 
from  wood,  or  from  pipe  fittings,  or  several  old  connecting  rods  may  be  bolted 
together  at  the  yoke  end  and  the  piston  fitted  onto  one  of  the  piston  pin  ends 
with  a  round  stick  in  the  other  piston  pin  end. 

4.  For  a  lapping  or  grinding  compound  it  is  best  to  use  a  valve  grinding 
compound,  selecting  a  grade  which  the  work  would  seem  to  require.  If  a 
coarse  compound  is  used  to  start  the  work,  the  finer  grades  must  be  used  to 
finish  it  and  to  remove  all  the  scratches.  Avoid  emery  compounds  for  this 
operation. 

.'j.  The  ideal  motion  for  the  work  of  lapping  or  grinding  is  a  revolving 
one.  supplemented  by  a  vertical  or  in  and  out  motion.  To  simply  work  the 
piston  up  and  down  in  the  cylinder  without  turning  it  will  not  grind  it  true. 
The  revolving  motion  is  essential  in  grinding  the  cylinder  round. 

6.  The  work  is  difficult  and  requires  patience  and  skill.  After  grinding  for 
a  considerable  time  the  piston  will  become  so  small  that  the  work  is  hindered. 
A  larger  piston  must  be  substituted,  or  the  one  in  use  must  be  split  with  a 
hacksaw  in  such  a  manner  that  the  two  sides  may  be  wedged  apart  a  bit  to 
compensate  for  the  wear. 

7.  When  the  cylinder  has  been  brought  to  a  fair  degree  of  accuracy  which 
can  be  determined  with  a  pair  of  inside  calipers  or  micrometers,  the  new  piston 
may  be  fitted.  To  do  this  use  fine  valve  grinding  compound  and  lap  or  grind 
in  as  suggested  for  the  use  of  the  old  piston. 

8.  The  clearance  of  the  new  piston  should  be  figured  according  to  the 
manufacturer's  specifications,  or  failing  knowledge  of  that,  the  allowance  may 
be  figured  as  follows: 

For  cast  iron  pistons  allow  .001"  to  .0015"  clearance  for  each  inch  cylinder 
diameter  at  the  top  of  the  piston.  The  skirt,  which  is  not  subject  to  as  great 
degree  of  heat,  may  be  made  a  closer  fit,  .00075"  per  inch  of  diameter  being 
recommended. 

For  aluminum  pistons  aflow  .003"  to  .004"  for  each  inch  of  cylinder  diameter 
at  the  top  of  the  piston.     Allow  somewhat  less  clearance  at  the  bottom. 

9.  Pistons  should  be  fitted  from  the  bottom  of  the  cylinders  and  in  their 
natural  position. 

10.  In  running  in  new  pistons  and  new  rings  care  must  be  exercised  to 
have  plenty  of  oil  and  not  to  operate  the  engine  at  excessive  speeds. 

JOB  70.     SCRAPING  OUT  CARBON. 

This  is  a  piece  of  work  readily  learned  by  the  student.  The  actual  work  of 
removmg  the  carbon  by  scraping  where  the  head  of  the  engine  may  be  removed 
is  slight. 

1.  Remove  the  head.     Job  65. 

2.  Scrape  all  the  carbon  from  the  tops  of  the  pistons,  the  valves,  and  the 
cylinder  block.     Use  a  putty  knife  and  screw  driver  to  scrape  with. 

3.  Scrape  all  the  carbon  from  the  cylinder  head.  Use  any  round  nose  tool 
to  work  into  the  corners. 

4.  If  plugs  need  it  clean  them  of  carbon.  Never  take  a  spark  plug  apart 
or  attempt  to  help  its  condition  as  long  as  the  porcelain  is  burned  a  clean  brown 
or  tan. 


174  Automotive  Trade  Training 

5.  Wipe  all  parts  free  of  carbon  and  carbon  dust. 

6.  Replace  head.     Jobs  66  and  67. 

7.  Where  the  head  is  cast  integral  and  it  is  desired  to  remove  the  carbon 
by  scraping,  the  first  step  is  to  remove  all  of  the  port  plugs. 

8.  Bring  the  piston  in  cylinder  No.  1  to  top  dead  center  on  compression 
stroke.     This  leaves  both  valves  closed. 

9.  While  in  that  position  proceed  to  scrape  the  carbon  loose.  Use 
compressed  air  to  blow  it  from  the  cylinder. 

10.  This  work  requires  patience  and  some  thought.  The  mechanic  must 
be  able  to  visualize  the  inside  of  the  combustion  chamber  and  the  work  of  his 
scraper.  He  can  not  see  how  the  work  is  coming.  He  will  in  time  learn  the  feel 
of  the  scraper  and  know  when  the  work  is  completed. 

11.  Scrapers  for  this  work  come  in  sets  of  three  and  are  made  from  cold 
rolled  steel.  In  special  cases  where  none  of  the  scrapers  seem  to  fit  they  may 
be  bent  to  such  shape  as  may  be  best,  or  other  special  scrapers  may  be  made  up. 

12.  When  each  of  the  cylinders  in  turn  has  been  finished  the  port  plugs 
are  cleaned.  These  plugs  will  frequently  give  as  much  trouble  with 
compression  leaks  as  would  a  removable  cylinder  head.  This  is  due  in 
practically  every  case  to  abuse  in  handling  them.  Proper  tools  to  turn  them 
are  not  at  hand  and  the  mechanic  uses  a  punch  and  hammer  to  turn  them.  This 
results  in  distortion  of  the  machined  seat  with  the  result  that  no  gasket  will 
make  them  tight. 

13.  To  prevent  trouble  at  this  point  it  is  good  practice  to  use  flake  or 
powdered  graphite  mixed  to  a  paste  with  machine  oil  to  coat  the  threads  with 
when  replacing  them. 

14.  Turn  the  port  plugs  in  snug.  Heat  the  engine  by  running  and  give  the 
plugs  another  turn. 


CHAPTER  7 

OILING  SYSTEMS 

To  facilitate  a  study  of  engine  lubrication,  the  main  types  of 
systems  only  will  be  mentioned.     These  are : 

1.  Splash. 

2.  Splash  and  circulating. 

3.  Force  feed. 

Of  the  latter  two  there  are  a  number  of  variations.     The  student 


\ 

1 

j 

Fig.  191.     Cadillac  Oiling  System. 

must  not  lose  sight  of  the  purpose  of  the  oiling  system  while  learning 
the  details  of  design. 

Full  Splash. — The  full  splash  is  not  used  in  automobile  engines 
today.  It  is  still  used  to  a  certain  extent  in  marine  and  stationary 
engines,  where  the  engine  remains  largely  in  a  level  position  and  is 
not  tilted  on  an  angle  for  considerable  length  of  time  as  in  hill  climb- 
ing. Here  an  outside  supply  is  arranged  to  drop  a  certain  amount 
of  oil  into  the  single  oil  reservoir  into  which  the  rods  are  dipped. 
Tilting  the  engine  runs  all  the  oil  to  one  end  of  the  oil  pan  and  while 
over  oiling  some  parts  it  is  under  lubricating  others. 

The  Splash  and  Circulating. — This  is  perhaps  the  most  popular 

175 


176 


Automotive  Trade  Training 


for  fours  and  sixes  as  it  is  not  so  likely  to  cause  trouble.  Here  oil 
is  carried  or  pumped  from  a  reservoir  to  a  second  level  in  the  oil  pan 
and  allowed  to  fill  up  oil  wells  or  grooves  into  which  the  rod  dippers 
may  dip  at  all  times.  To  accomplish  this  result  satisfactorily  each 
rod  has  its  own  well,  and  coming  onto  a  hill  does  not  materially 
disturb  the  lubrication  as  the  circulating  system  keeps  the  oil  sup- 
plied to  these  wells  from  which  it  is  splashed  up  into  the  cylinder 
walls,  piston  walls,  valve  ports,  and  onto  piston  rods,  piston  pins, 
valve  tappets,  cams,  cam  shaft  bearings,  and  timing  gears.     Besides, 


Fig.  1^-  Overland  Splash  and  Circulating  Oiling  System.       • 

a  vapor  is  even  supplied  to  valve  stems,  and  springs  inside  the  in- 
spection plates,  or  under  the  valve  cage  covers. 

Usually  the  oil  pan  is  made  with  two  levels,  the  lower  level 
acts  as  an  oil  reservoir,  while  the  upper  is  the  one  which  contains  the 
oil  grooves.  As  long  as  there  is  oil  in  the  lower  level  sufficient  to 
fill  the  pump  well,  or  sump,  the  pump  keeps  the  oil  flowing  to  the 
upper  level  from  which  it  is  splashed  and  used  to  lubricate  moving 
parts  as  indicated  in  Fip".  192.  All  surplus  oil  finds  its  way  back  to 
the  lower  oil  level  ready  to  be  recirculated. 

Forced  Feed. — There  are  several  varieties  of  force  feed.  This  is 
particularly  adaptable  to  the  V  type  motor,  as  all  attempts  to  use  the 
splash  system  here  have  resulted  in  failure,  due  to  more  oil  being 
splashed  into  the  left-hand  block  (from  driver's  position)  over- 
lubricating  it,  and  under-lubricating  the  right-hand  block. 


Oiling  Systems 


177 


Fig. 


193.    Buda  Engine.    An  example  of  the  Pull  Forced  Feed  oiling  system.     Note  the 
drilled  crank  shaft  and  the  direction  of  travel  of  the  oil  through  it. 


In  the  force  feed  system  the  oil  is  circulated  from  the  oil  sump 
in  the  oil  pan  through  a  screen  into  the  circulating  tubes,  into  the 
main  bearing  caps,  from  where  it  finds  its  way  through  oil  grooves 
and  holes,  into  the  crank  shaft  which  has  either  holes  or  tubes  provided 
for  carrying  the  supply  to  the  crank  pins  within  the  rod  bearings. 
From  this  point  the  oil  is  sprayed  onto  the  cylinder  walls  and  piston 
pins,  cams,  tappets,  etc. ;  or  in  what  is  termed  full  force  feed  the  oil  is 
forced  still  farther  and  carried  up  through  the  connecting  rod,  or  along 
it,  through  a  tube  to  the  piston  pin,  from  which  it  is  forced  to  the 
piston  bushings  and  cylinder  walls  and  rings.  The  cam  shaft  bearings 
are  also  fed  by  oil  under  pressure,  while  the  cams,  valve  lifters,  gears 
and  chains  are  very  largely  dependent  on  splash,  even  in  the  full  force 
feed. 

While  the  splash  of  oil  often  plays  a  very  distinct  part  in  the 
force  feed  the  student  must  remember  that  there  are  no  dippers  on  the 
rods,  nor  is  there  any  provision  for  the  rods  to  dip  into  the  oil  and 
splash  to  the  other  parts.  Rather  the  unused  portions  or  surplus  of 
oil  forced  to  the  engine  bearings  are  sprayed  or  splashed  or  thrown  ofT 
as  the  shaft  turns.     Fig.  195. 

Oil  Pumps. — In  automobile  engine  oiling  systems,  the  oil  is  cir- 


178 


Automotive  Trade  Training 


culated  by  means  of  pumps, 
except  in  the  case  of  the  Ford, 
where  the  oil  is  carried  up  to 
the  top  of  the  flywheel  hous- 
ing by  the  flywheel,  where  a 
certain  amount  is  caught  in  the 
funnel  shaped  opening  of  the 
oil  circulating  tube  and  then 
flows  by  gravity  to  the  front 
end  of  the  engine.  Other  sys- 
tems utilize  the  gear  pump,  the 
rotary  vane  or  centrifugal 
pump,  and  the  plunger  type 
pump. 

Centrifugal  or  Rotating 
Vane  Pump. — This  type  of 
pump  as  used  in  the  Dodge 
consists  of  a  vane  or  impeller 
so  driven  that  oil  is  draw^n 
from  the  oil  sump  coming  into 
the  oil  pump  case,  then  thrown 
off  and  out  at  another  opening, 
thus  finding  its  way  to  the 
bearings,  oil  wells  and  grooves. 


Fig 


Buda  Kiifiiiie.  Timing  Gear  end 
view  of  tlie  Full  Force  Feed  oiling  system. 
Note  the  operation  of  the  Geared  oil  pump 
and  the  saber  type  of  oil  gauge.  Note  parts 
lubricated   by   splash. 


— Jf     *         XS                                 M_ll^^                                ^^1             m 

g 

r 

Fig.  195.    Continental  Red  Seal  7R.    Full  Pressure  Lubricating  System. 


Oiling  Systems 


179 


Fig.  190.     Haynes  Gear  Type  Oil  Pump. 


Gear  Pump. — In  this  case  oil 
is  taken  into  the  oil  pump  case 
and  thrown  off  by  two  small  gears 
having  teeth  of  coarse  pitch. 
These  gears  are  driven  from  the 
engine  and  oil  coming  in  goes 
ai;^und  the  gears  and  not  be- 
tween them.  A  small  quantity  is 
carried  between  each  tooth  and 
the  pump  case,  much  as  the  old 
chain  pump  carried  successive 
cups  of  water  to  the  top  of  the 
well  and  dumped  it  in  a  flowing 
stream  from  the  spout  of  the 
pump.  Oil  coming  from  one  side 
meets  that  coming  around  the 
gear  from  the  other  side  and  more 
and  more  is  brought  around ;  cir- 
culation is  started  and  continues 
as  long  as  oil  remains  or  the 
engine  continues  to  operate. 

Plunger  Type  Pump. — In  the  plunger  type  pump  commonly  used 
on  the  force  feed  system,  oil  is  drawn  into  the  pump  body  after  which 
a  valve  closes ;  as  the  plunger  descends  the  oil  must  be  forced  out. 
An  opening  with  another  one-way  valve  is  provided  for  this.  After 
the  oil  has  been  forced  out  the  plunger  starts  upward  again,  when 
the  second  valve  closes  to  prevent  oil  being  drawn  from  the  lubrica- 
tion line  rather  than  the  oil  sump  or  well.  However,  the  first  valve 
has  again  opened  and  permits  oil  to  enter.  The  operation  continues 
regularly,  the  check  valves  controlling  the  direction  of  flow.  The 
amount  of  flow  is  controlled  by  adjusting  the  length  of  stroke  on  the 
plunger  which  is  usually  operated  by  cam  action. 

Indicating  Devices. — There  are  two  general  methods  of  indicat- 
ing the  working  of  the  oiling  systems,  the  sight  feed  and  the*  pressure 
gauge. 

Sight  Feed. — In  the  case  of  the  sight  feed  a  small  metallic  case 
with  a  glass  dial  is  placed  on  the  dash  or  instrument  board.  As  the 
oil  is  circulated  by  the  pump  it  is  carried  to  the  sight  feed  into  which 
it  may  be  seen  flowing.  A  small  vane  is  mounted  in  the  instrument 
at  times  in  order  that  the  action  or  flow  of  oil  may  be  more  readily 
detected.  From  the  sight  feed  the  oil  returns  to  the  engine  where  it 
is  used  to  lubricate  the  moving  parts.  > 

Pressure  Gauge. — In  the  case  of  the  pressure  indicator  the  opera- 
tion ;is  similar  to  that  of  the  air  or  steam  gauges.  Pressure  in  oiling 
systems  varies  from  two- or  three  pounds  to  as  much  as  fiftyjn  some 


180 


Automotive  Trade  Training 


Oiling  Systems 


181 


Oii  Li^-ft  feedtng  flecker  Armt 
Each  R^ct-er  Afm  Ped  tndividuBlly 


Small  Stand  Ftps  to  Give 
Constant  Oil  Pressof*  Feed 
to  Bc-j^fif  Arrr.a 


\ 


Line  FeBOino 
Ganeratof  Gear 
eat  Bejflna 


Overflow  from 
cut  Preeaure 
Reflulator  Oiro«te<l 


Outline  o«  0*1  W«y  (n  Fnmt 

Mrmg  Biwhino  ConfWCtmo 

O.i  L.oe  tn  Cr^nkshalt  with  Une» 

to  Oil  Pres«ur»  Regulotor  »rtD 

Camshaft  Susntng 


/ 


Fig.  198.    Phantom  view  of  Marmon  Force  Feed  Oiling  System. 


high  Speed  motors.  In  all  cases  the  higher  the  speed  the  greater  the 
oil  pressure.  The  pressure  gauge  is  mounted  on  the  instrument  board. 
A  single  copper  tube  runs  from  it  and  is  connected  to  the  oil  lines. 
Oil  flowing  in  the  lines  would  also  tend  to  flow  to  the  gauge.  Since, 
however,  this  line  is  filled  with  air,  the  oil  cannot  reach  the  instru- 
ment, and  it  is  the  air  which  actually  registers  the  oil  pressure.  Thus, 
as  the  pump  develops  pressure  it  is  registered  on  the  gauge.  These 
indicators  are  placed  on  the  dash  in  order  that  the  operator  may 
know  with  some  assurance,  the  condition  of  the  oiling  system.  As 
long  as  oil  continues  to  flow  through  the  sight  feed,  the  driver  may 


182 


Automotive  Trade  Training 


STROKE  CONTROL  'STROKE  '"  C  "  TPC 

SLOW  SPEED  HfGH  SPEED 


STROKE  ALLOWED 

BY  CONTROL  IN 

SLOW    SPEED   POSITION 


STROKE  ALLOWED 

BY^CONTROL  IN 
!GH  SPEED   POSITION 


OIL  RESERVOIR 
DRAIN  PLUG 


Fig.  199.    Hudson  Oil  Pump  Plunger  Type. 

know  that  there  is  oil  in  the  motor  and  the  system  is  working.  If 
the  oil  fails  to  flow,  the  engine  should  be  stopped  immediately  and  the 
supply  investigated.  If  the  oil  is  low,  refill.  If  this  fails  to  correct 
the  trouble  the  pump  should  be  primed.  Should  this  fail,  the  pump 
should  be  investigated  for  possible  trouble  and  the  oil  line  blown  out 


Oiling  Systems 


183 


k 


kV\^^S.S\->^VVV\KK\S^i^ 


PUMP  OUTLET 
CONNECTION 


DAiH   CAUOE  . 

Pipe  CONNECTION 


OIL  P^JHP  I0W6R  GEAft 


(AH  SHAFT 


0»L  PUt^P  DRIVING 
— •  0EAR5 


.OIL  PUMP  SHAFT 

erARiNC 

J>iL  PUMP  5HAFT 


UPPER  CffANK  CASE 


.OIL  PUMP  SCRUN 


,OlLPUMP  ORive 
GEAR 

OIL  PUMP  COV&R 

OIL  PUMP  SCREEN 
COVER 


Fig.   200.     Buick   Oil  a'uinp. 


184 


Automotive  Trade  Training 


Fig.  201.    Continental  7R  showing  Gear  Type  Oil  Pump. 

with  compressed  air.  The  screen  in  the  oil  sump  at  times  is  clogged 
with  dirt  and  must  be  cleaned.  Failure  of  the  pressure  to  register 
may  be  due  to  a  broken  line,  thinned  oil,  a  clogged  tube,  etc.  In  the 
case  of  full  force  feed,  if  the  pressure  gauge  shows  a  sudden  jump 
above  normal  pressure,  it  may  be  due  to  dirt  in  the  line  or  stoppage 
of  some  of  the  passages.  Failure  of  any  of  the  oil  lines  is  pretty 
certain  to  result  in  badly  scored  or  burned  parts;  usually  some  in- 
dications of  approaching  trouble  may  be  detected  on  the  gauges, 
either  sight  feed  or  pressure.     Since  cold  always  tends  to  make  oil 


Fig.  202.     Packard  Truck  Gear  Type  Oil  Pump. 


Oiling  Systems 


185 


heavier  or  thicker,  the  pressure  on 
the  gauge  will  show  more  in  start- 
ing the  engine  than  after  the  engine 
warms  up. 

Caring  for  Oiling  Systems. — A 
properly  functioning  oiling  system, 
properly  cared  for,  will  do  more  to 
lengthen  the  amount  of  service  to  be 
obtained  from  an  engine  than  any 
other  one  thing.  No  system  is 
flawless.  No  engine  is  flawless. 
Careless  operation  of  the  engine 
increases  the  likelihood  of  trouble. 
The  exercise  of  proper  care  may  do 
much  to  eliminate  the  development 
of  trouble. 
^,     «««    «    ,     ,  „,     ,    ^.,  «.    .  Oil  Wears  Out. — The  grade  of 

Fig.    203.    Packard    Truck   Oil   Strainer  .,  ,  .     .  ,,    ^ 

and  Relief  Valve.  Oil    to    be    uscd    IS    usually    recom- 

mended by  the  manufacturer  of  the  motor  car.  Generally  speaking, 
the  older  the  car  the  looser  the  parts  have  become,  due  to  natural 
wear,  and  the  heavier  the  oil  permissible  and  desired.  No  matter 
what  the  grade  or  quality  of  oil,  it  will  wear  out.  The  purpose  it 
serves  is  to  provide  a  film  between  two  metals  to  prevent  them  touch- 


Fig.  204.    Continental  7R  showing  Oil  Strainer,  Oil  Lines,  Floats,  and  Gauge. 


186 


Automotive  Trade  Training 


Fig.  205.     King  Oiling  System. 

ing  each  other.  This  is  necessary  to  prevent  wear  as  they  perform 
their  vv^ork,  as  for  instance  in  the  crank  within  its  bearing,  the  shaft 
actually  rides  on  the  oil.  The  oil  might  be  said  to  act  similarly  to  the 
balls  between  the  outer  and  inner  race  in  a  ball  bearing.  To  provide 
for  a  heavier  load,  in  the  latter  case,  larger  balls  are  used  or  a  greater 
number  of  smaller  ones.  In  the  engine  bearing,  the  greater  the  load 
the  greater  the  bearing,  consequently  the  larger  the  film  of  oil  carrying 
the  load.  As  the  engine  runs  the  oil  is  worn  round  and  round  in  the 
bearings.  It  is  hammered  by  the  impact  of  the  piston  l)lows,  and 
ground  between   the   piston   and   cylinder   wall.     In   this   way   small 


Cork  npaf- 


~-0/l  finer  ^screen 

Touch  mm  r/rj<^er.  - 
u//7e/7  fill/ncf,  to  injure 


~3e/7£f  Wis  ca/re  //  neceO'Sari^ 
to  make  /nd/cafor  read  correcf/i/. 


Fig.  20(j.     Keo   Oil  Gauge  and   Filling  Tube. 


UlLlNG    ^VSTE-\ 


187 


particles  of  metal  are  picked  up.  Carbon  and  gasoline  also  are 
carried  down  by  it  from  the  combustion  chamber  and  it  gradually 
accumulates  such  a  quantity  of  foreign  materials  that  it  is  no  longer 
fit  for  lubrication. 

Draining  Oil.- — When  this  condition  is  present  it  is  necessary  to 
draw  the  oil  from  the  crank  case,  flush  and  refill  with  new  oil.  This 
should  be  done  each  thousand  miles  the  car  is  run,  during  the  summer. 


m 

'  !  .-.,..    :;.■    I 

mmm^-—^^. 

M 

'^^TW- 

iSHi^tt^          l^tlM' 

#%i  ■; 

1 r ^ 

^  ^rm-^ 

.¥T i 

r^ 

^4---iM" 

Fig.  207.     Buick  Motor. 


In  winter  it  may  be  necessary  to  drain  the  oil  more  often  as  the  heavy 
grades  of  gasoline  are  hard  to  vaporize  and  more  will  be  drawn  into 
the  cylinder  than  is  burned.  This  works  down  into  the  oil  and  thins 
it  out. 

New  cars,  or  cars  just  overhauled,  should  have  the  oil  drawn  from 
the  engines  after  not  more  than  500  miles'  service. 

Troubles  Due  to  Loss  of  Lubricating  Qualities. — Destroying  the 
lubricating  qualities  of  the  oil  brings  about  many  unsatisfactory  con- 
ditions, for  which  there  is  no  apparent  cause.  These  conditions  are 
usually  difficult  for  the  inexperienced  driver  to  comprehend.  Some 
of  the  troubles  which  are  a  direct  result  of  the  impaired  qualities  of 
the  lubricating  oil,  are  as  follows: 

1.  Hard  starting. 

2.  Premature  piston  wear. 

3.  Premature  cylinder  wear. 

4.  Premature  piston  ring  wear. 


188 


Automotive  Trade  Training 


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9 

1 

pi 

^ 

1? 

f' 

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J 
^ 

■ 

1 

V 

^ 

I 

/ 

7 

^ 

r 

r 

1 

I 

c 

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5 

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^ 


Oiling  Systems  189 

5.  Connectingf  rod  bearings  burning  out. 

6.  Crank  shaft  bearings  burning  out. 

7.  Excessive  gasoline  consumption. 

8.  Smoking  due  to  the  abnormal  increase  in  the  height  of  oil 
level  in  the  crank  case  on  account  of  gasoline  working  into 
the  base  of  the  motor. 

9.  Excessive  carbon  in  cylinder. 

10.  Tendency  to  overheat,  due  to  lack  of  lubrication. 

11.  Very  poor  or  no  compression. 

All  of  the  above  result  in  lack  of  power  and  poor  performance. 
This  diluted  mixture  tends  to  soften  the  carbon  and  practically  makes 
a  carbon-gasoline  lapping  compound  which  has  a  tendency  to  aggra- 
vate the  wear  already  caused  by  parts  running  without  adequate 
lubrication. 

To  eliminate  so  far  as  possible  the  above  conditions: 

1.  Keep  motor  free  from  carbon. 

2.  Replenish  regularly  the  oil  supply  in  the  engine  base.  For 
trucks  in  constant  service  this  should  be  done  every  week  in 
cold  weather,  decreasing  to  once  a  month  in  the  heat  of 
summer. 

3.  Use  choke  sparingly. 

4.  Do  not  adjust  carburetor  to  give  a  rich  mixture.  This  helps 
in  starting,  but  the  excess  fuel  eventually  finds  its  way  to 
the  oil  reservoir.  Always  make  carburetor  adjustments  after 
the  motor  has  run  for  some  time  and  is  thoroughly  warmed 
up.  , 

5.  Use  best  grade  of  gasoUne  obtainable,  especially  in  cold 
weather. 

JOB  71.     CLEANING  VALVB  STEMS;  AND  GUIDES,  AND  PISTON 

RINGS. 

Dtte  to  the  oily,  gumnny  carbon-like  deposits  around  the  piston  rings  and 
about  the  valve  stems  and  guides,  it  is  a  good  plan  to  treat  these  points  with 
kerosene  each  thousand  miles  pf  service.  To  do  this  will  insure  better  power, 
compression,  and  lubrication,  fewer  repair  bills,  and  smaller  gasoline  and  oil 
bills.     This  operation  may  be  carried  out  as  follows: 

1.  Do  this  work  just  before  draining  the  oil  as  indicated  in  Job  72.  This 
is  in  order  to  prevent  an  undue  waste  oi  engine  oil  since  it  is  necessary  to 
drain  the  oil  after  the  process  indiicated  here  is  finished. 

2.  Open  up  the  auxiliary  air  valve,  or  carburetor,  in  such  manner  that  the 
end  of  a  rubber  tube  or  of  the  oil  gun  may  be  inserted.  With  the  engine 
operating  under  its  own  power  the  oil  gun  is  used  to  feed  kerosene  into  the 
carburetor  just  as  fast  as  the  engine  will  take  it  without  choking  and  stopping. 
If  the  engine  tends  to  stop,  the  throttle  should  be  opened  and  closed  rapidly, 
which  operation  will  likely  keep  it  running  until  the  kerosene  has  been  worked 
through  the  engine.  Run  from  one  quart  to  two  quarts  through  the  engine  in 
this  manner,  depending  on  the  number  and  size  of  the  cylinders. 

3.  Remove  the  inspection  plates.     Spray  or  squirt  the  kerosene  onto  and 


190  Automotive  Trade  Training 

into  the  valve  guides,  valve  springs,  tappets  and  tappet  guides,  working 
down  and  out  the  old  grease  and  loosening  the  gummy  accumulations  about 
the  valves  and  guides. 

4.  Clean  all  surplus  oil  from  the  tappet  compartments,  and  clean  up  the 
engine  where  the  kerosene  and  oil  have  run  over. 

5.  Replace  the  inspection  plates,  after  they  have  been  cleaned  and  freed 
of  dirt  and  grease. 

6.  Proceed  to  drain,  oil  and  flush  the  crank  case  as  directed  in  the  next 
job  sheet. 

JOB  72.     GENERAL  INSTRUCTIONS  FOR  DRAINING,  FLUSHING 
AND  REFILLING  THE  ENGINE  CRANK  CASE. 

It  is  impossible  to  sufficiently  emphasize  the  need  of  proper  care  of  the 
engine  oiling  system.  New  cars  and  even  used  cars  find  their  way  into  the 
repair  garage  much  more  frequently  than  would  be  necessary  if  the  oiling 
systems  were  cared  for  according  to  the  directions  of  the  car  manufacturer. 
Not  all  engines  may  be  drained,  flushed  and  refilled  in  the  same  manner.  Two 
examples  are  given  in  Jobs  73  and  74.  These  directions  are  according  to  the 
specifications  of  the  manufacturer  in  each  case.  In  the  one  the  engine  is  to  be 
cranked  with  the  kerosene  in  the  engine,  in  the  other  the  motor  is  not  to  be 
cranked  with  the  kerosene  in  the  crank  case.  Wherever  possible  to  obtain  the 
car  manual  it  should  be  followed  most  carefully. 

In  every  case,  it  is  absolutely  essential  that  the  old  oil  be  drained  and  thu 
crank  case  flushed  and  washed  out  with  kerosene  once  for  each  thousand  miles 
of  service.  Where  the  car  manual  is  not  at  hand  the  following  directions  may 
be  safely  followed: 

1.  Warm  up  the  engine  a  bit  to  get  the  old  oil  flowing. 

2.  Remove  drain  plug  and  drain  ofif  oil  into  a  bucket. 

3.  By  shaking  the  car  it  is  frequently  possible  to  run  out  additional  oil, 
after  it  would  otherwise  have  stopped  flowing. 

4.  Replace  plug  in  drain. 

5.  Pour  in  from  two  to  four  quarts  of  kerosene. 

6.  Either  run  the  engine  under  its  own  power,  for  30  seconds  at  a  slow 
speed,  or  operate  it  with  the  starter  for  a  like  space  of  time,  or  by  placing  one 
foot  on  each  horn  of  the  frame  the  mechanic  can  so  use  the  weight  of  his  body 
as  to  get  the  engine  swinging  up  and  down  in  such  a  manner  that  the  kerosene 
will  be  splashed  over  the  interior  parts  of  the  engine  and  wash  down  a 
considerable  amount  of  dirt  accumulation.  (Use  care  to  protect  the  paint  in 
this  operation.) 

7.  Remove  the  drain  plug  again  and  drain  oflf  the  kerosene.  Shake  the 
car  by  the  above  mentioned  method  to  keep  the  dirt  from  settling  while  the 
kerosene  is  being  drained. 

8.  Allow  the  drain  plug  to  remain  out  while  the  new  supply  of  oil  is  slowly 
poured  into  the  oil  filler  tube. 

9.  When  the  oil  starts  to  flow  clear  and  without  signs  of  any  more 
kerosene  the  drain  plug  is  replaced  and  the  engine  filled  to  the  proper  oil  level. 

10.  Where  oil  strainers  are  in  use  they  should  be  removed  each  one 
thousand  miles  and  thoroughly  cleaned. 

JOB  73.     DRAINING  OIL  FROM  PACKARD  ENGINE. 

Drain  and  flush  the  crank  case  of  the  Packard  Twin  Six  each  500  miles  in 
the  winter  and  each  750  to  1000  miles  of  service  in  the  summer  months. 

1.  Remove  the  oil  plugs  from  the  bottom  of  the  crank  case  and  from  the 
oil  pump  housing. 


Oiling  Systems 


191 


2.  After  the  old  oil  is  all  drained  off  the  crank  case  is  flushed  out  by- 
running  kerosene  through  the  oil  filler. 

3.  Thoroughly  clean  the  oil  pump  and  strainer  but  do  not  run  engine. 

4.  After  the  kerosene  has  been  drained  the  crank  case  should  be  filled 
with  two  and  three-fourths  gallons  of  oil  which  is  the  amount  required  to 
bring  it  to  the  oil  pet  cock  level. 

6.    Do  not  fill  above  the  oil  pet  cock  level. 

JOB  74.     DRAINING  OIL  FROM  HUDSON  ENGINE. 

1.  Remove  the  drain  plug  from  the  bottom  of  the  oil  reservoir,  draining 
off  all  old  oil.  Shaking  the  car  will  frequently  bring  down  more  oil  after  all 
has  seemed  to  have  drained.     Note  Fig.  209. 


i\ 

1 

,     K 

«* 

i 

jf 

•     1 

Fig.  209.     Draining  off  Dirty  Oil. 


Fig.  210.     Pouring  in   Kerosene   (Hudson). 


2.  Remove  the  valve  cover  plates  and  pour  about  a  quart  of  kerosene  into 
each  tappet  compartment.     Fig.  210. 

3.  Crank  the  motor  with  starter  for  about  30  seconds.  Do  not  allow  the 
motor  to  operate  under  its  own  power.  This  will  wash  down  all  sediment  and 
dirt  from  the  inside  walls  and  oil  troughs. 

4.  Remove  the  drain  plug  and  drain  off  all  kerosene,  allowing  at  least  3 
minutes  for  draining. 

5.  Pour  clean  oil  into  the  tappet  compartments.  As  this  oil  is  poured 
into  the  compartment  slowly,  it  runs  into  the  oil  troughs  and  displaces  the 
kerosene  left  from  the  previous  operation.  This  kerosene  is  allowed  to  flow 
out  of  the  drain  before  the  drain  plug  is  replaced.  The  plug  is  only  replaced 
after  the  lubricating  oil  starts  to  flow  from  the  drain  in  a  clean  stream. 

6.  Refill  with  seven  quarts  of  clean  new  oil. 

JOB  75.     CLEANING  AN  OIL  PAN. 

Even  with  the  care  given  an  oiling  system  as  suggested  previously,  the 
continuous  use  of  the  car  from  month  to  month  and  season  to  season  will  cause 
an  accumulation  of  dirt  and  sediment  in  the  oil  pan  which  is  difficult  to  remove 
without  actually  removing  the  crank  pan  or  oil  pan.  This  is  an  operation  for 
which  only  general  directions  can  be  given. 

1.  Remove  the  pan  bolts  and  drop  the  pan  down,  having  first  drained  away 
the  oil. 

2.  Take  the  pan  to  the  bench  or  cleaning  trough  and  carefully  remove  the 
sediment,  and  clean  each  and  every  nook  and  corner. 

3.  Blow  out  the  oil  passages  and  make  certain  that  nothing  impedes  the 
ilow  of  oil  through  them. 

4.  Clean  the  oil  strainers  and  any  other  parts  attached  to  the  pan. 


193 


Automotive  Trade  Training 


Fig.  211.     Cranking  Motor  30  seconds   (Hudson). 

5.  Use  compressed  air  to  blow  out  all  oil  lines  left  on  the  engine. 

6.  Inspect  and  clean  the  interior  of  the  engine.  Wash  out  with  kerosene. 
See  that  all  oil  holes  to  bearings  are  clean  and  free. 

7.  If  the  bearings  are  loose  they  should  be  put  in  shape  at  this  time; 
however,  the  need  of  bearing  adjustment  is  postponed  indefinitely  in  many 
cases  simply  by  properly  caring  for  the  oiling  system. 

8.  Replace  the  pan  and  make  all  connections  as  formerly. 

9.  It  may  be  necessary  to  use  new  oil  pan  gaskets  to  insure  a  tight  joint. 


Fig.  212.    Refilling  with  Cleau  Lubricating  Oil  (Hudson). 


CHAPTER  8 


COOLING  SYSTEMS 


There  are  two  types  of  air  cooling  systems  in  use  today.  These 
are  direct  and  indirect. 

Direct  Air. — The  Franklin  is  the  best  example  of  direct  air  cool- 
ing. Here  the  air  is  drawn  in  through  the  hood,  passes  into  a  cham- 
ber over  the  cylinders,  then  down  along  the  cylinders  which  have 
cooling  vanes  cast  on  them,  and  is  thrown  off  or  out  at  the  rear  of 
the  engine  through  the  flywheel  fan.     The  cooling  is  more  or  less 

'Radiator  Cap 

■Filler  Neck 

■  Top  Tank 

"Splash  Plate 

"Overflow  Tube 

'Kadiator  Tubes 

'Kad  Inlet  Cona 

'Cyl  Outlet  Hose 

'Hose  Clip 

„_  .--^  Cylinder  Head 

Cylinder  Casting 

Cylinder  Inlet  Connection 


Fig.   213.    Ford   Thermo-Syphon   Cooling   System. 
independent  of  the  car  speed,  being  controlled  almost  altogether  by 
the  engine  speed.     Low  speed  gear  work  does  not  seem  to  overheat 
the  motor  as  is  often  the  case  in  the  indirect  air-cooled  systems. 

Indirect  Air. — In  this  case  the  engine  cylinders  are  jacketed  to 
carry  a  supply  of  water.  The  main  supply  of  water  is  carried  in  the 
radiator.  As  the  engine  is  operated  the  water  around  the  cylinders 
is   heated,   after   which   it   is   circulated   upward   to   the   top   of   the 


194  Automotive  Trade  Training 

radiator,  from  which  point  it  is  passed  downward  through  the  radia- 
tor tubes,  or  cells,  and  the  heat,  extracted  from  the  cyhnder  walls  by 
the  water,  is  now  extracted  from  the  water  by  the  air  in  contact  with 
the  large  surface  area  of  the  radiator  cells  or  tubes  and  vanes.  When 
the  cooled  water  has  come  to  the  bottom  of  the  radiator  it  is  again 
passed  or  circulated  upward  through  the  cylinder  blocks  where  it  is 
again  reheated,  thence  on  to  the  radiator  where  it  is  recooled ;  and  so 
on  as  long  as  the  engine  is  running.  In  this  system  the  water  is 
used  as  a  medium  of  transmitting  the  heat  from  the  engine  to  the  air, 
instead  of  having  the  air  come  in  direct  contact  with  the  engine 
cylinders. 


Fig.    214      Buick    Cooling    System. 

Water  Cooling. — The  indirect  air  is  known  as  a  water  cooling 
system.  Here  again  we  have  two  general  classes,  each  with  its 
peculiar  advantages. 

Thermosiphon. — The  thermosiphon  is  the  most  popular  for  the 
lighter  cars.  Its  use  does  away  with  the  necessity  of  a  pump  with 
its  attendant  parts  and. troubles.  Circulation  here  is  established  by 
the  action  of  a  natural  law.  When  water  is  heated,  those  portions 
of  it  in  contact  with  the  heat  expand,  become  lighter,  and  rise  to  the 
top.  Portions  on  top  and  cooler  will  settle  where  they  in  turn  are 
heated  to  a  point  above  that  of  the  water  now  on  top,  when  it  is 
displaced  and  returned  to  the  bottom  for  more  heat.  Circulation  is 
continuous  so  long  as  heat  is  applied.  The  word  "thermo"  meaning 
heat,  and  "siphon"  to  draw  out,  might  be  said  in  this  instance,  to  mean. 
to'  draw  out  the  heat  from  the  engine.  To  facilitate  a  rapid  circula- 
tion in  this  case,  the  radiator  inlet  and  outlet  is  made  large.  An 
advantage  of  this  type  is  that  an  engine  will  warm  up  more  readily 


Cooling  Systems 


195 


than  one  where  the  pump  is  used,  as  the  water  does  not  start  circulat- 
ing until  it  is  heated.  One  disadvantage  is  that  the  water  may 
freeze,  in  cold  weather,  in  the  lower  parts  of  the  radiator  before 
circulation  is  fully  established. 

Forced  or  Pump  Circulation. — In  this  case  the  water  circulates 
in  the  same  manner  as  in  the  thermosiphon,  but  a  mechanically  driven 
pump  is  used  to  keep  the  water  circulating.  The  pump  is  used  to 
draw  the  water  from  the  lower  part  of  the  radiator  and  force  it  into 
the  lower  part  of  the  cylinder  block,  from  which  point  it  follows  the 
usual  path.  Circulation  is  established  immediately  and  positively. 
Smaller  water  connections  and  hose  are  used  than  in  the  case  of  the 
thermosiphon. 


Fig.  Iil5.  Packard  Truck  Cooling  System.  Note  the  thermostatic  control  which 
keeps  the  water  passage  to  the  radiator  closed  until  the  water  within  the  cylinder 
block  has  come  to  a  temperature  allowing  eflBcient  operation  of  the  engine.  As  the 
engine  continues  to  run  after  reaching  this  point  in  temperature  the  thermostat 
gradually  opens  until  sufficient  water  flows  to  keep  the  engine  at  this  point  of 
greatest   efficiency. 

Cooling  System  Care. — The  careful  driver  or  mechanic  never 
fails  to  give  the  cooling  system  daily  inspection.  Usually  a  s^mall 
quantity  of  water  daily  is  sufficient  to  keep  all  working  smoothly.  The 
sudden  and  unusual  disappearance  of  water  means  trouble ;  it  may 
mean  a  leaky  radiator  hose  connection  or  something  more  serious, 
as  leaking  cylinder  head  gaskets,  a  broken  or  damaged  radiator,  or 
other  parts.  Whatever  the  trouble  is,  it  should  be  located  and 
remedied  immediatelv.  r 


196 


Automotive  Trade  Training 


Radiator  Hose. — Owing  to  the  fact  that  the  automobile  is  in  use 
on  uneven  as  well  as  smooth  surfaces,  there  must  be  a  degree  of 
flexibility  between  the  various  units.  To  permit  this  movement  be- 
tween the  radiator  and  engine,  rubber  hose  is  used  to  form  the  water 
connection.  Hose  bands  or  clips  are  used  to  bind  the  hose  in  posi- 
tion. Occasionally  shellac  is  used  to  make  a  tight  joint,  but  should 
not  be  used  unless  the  leak  cannot  be  stopped  otherwise. 

Rubber  Hose  Troubles. — Due  to  the  moisture,  heat,  vibration, 
bending  and  twisting  to  which  the  hose  is  subjected,  it  will  wear 
out  and  need  to  be  replaced  occasionally.  Length  of  service  is  no 
indication  of  condition.  The  hose  may  last  two  weeks,  two  months, 
or  two  years.  One  year  may  be  a  conservative  average.  Usually  the 
hose  peels  away  on  the  inside  first,  and  this  inner  rubber  lining  break- 
ing lose  may  cut  off  all  circulation  through  the  hose.  Again  it  may 
be  carried  into  the  vital   parts   of  the   circulating  system   and   clog 


I^adiator 

ran  t?e/r  adjustment 

Pack/nq  <:f/ands 
Tyater  out/ef 

Water  infet 

JVater  pump 


Fig.  216. 


Reo  Water  Circulation  System.    Arrows  indicate  the  direction  of  flow 
of  the   water. 


Cooling  Systems 


197 


them.    Naturally  less  resistance  is  needed  to  retard  circulation  in 
the  thermosiphon  system  than  in  the  forced  circulation. 

Steaming  Radiator. —  This  is  an  indication  of  lack  of  water  or 
failure  to  circulate.  Failure  to  circulate  may  be  due  to  a  frozen 
radiator  or  passages,  or  a  broken  down  rubber  hose  or  pump.  If  a 
radiator  filled  with  water  starts  steaming  on  a  cold  day  the  trouble 
is  obvious,  likewise  the  remedy.  Leaving  the  car  set  with  the  radia- 
tor covered  will  often  thaw  out  the  troublesome  spot.  If  this  does 
not  avail,  it  will  be  necessary  to  get  the  car  into  a  warm  garage. 


Fig.    217.     Packard    Twin    Six    Cooling    System.     Thermostat    in    Detail. 

If  the  trouble  is  in  the  hose  it  may  be  detected  sometimes  by 
exerting  pressure  on  the  outside  of  the  hose.  ,  This  is  not  always 
true  however  and  the  hose  may  have  to  be  removed  and  inspected. 
When  this  fails,  inspect  other  parts.  The  impeller  on  the  pump  shaft, 
may  have  worked  loose,  or  other  mechanical  trouble  may  have 
developed.  A  systematic  search  must  be  made  and  the  trouble  cor- 
rected. 

Radiator  Mountings. — To  prevent  unusual  jars  and  twists  being 
transmitted  to  the  radiator,  springs,  swivels  or  bufifers  of  some  kind 
are  provided.  A  radiator  not  so  provided,  as  in  older  types,  may  be 
protected  by  having  a  piece  of  rubber  mounted  under  the  supports. 

Radiator  Types. — In  designing  radiators  having  large  surface 
areas  exposed  to  cooling  drafts  of  air  as  it  is  drawn  through  the  radia- 
tor core,  several  distinct  types  have  been  developed.  Very  thin 
copper  is  used  to  construct  the  vanes  and  tubing  or  cells,  to  insure 


198 


Automotive  Trade  Training 


rapid  radiation  of  the  heat  from  the  water.     The  types  in  use  are  the 
tubular  and  the  honeycomb  or  cellular. 

Tubular  Type. — This  is  the  most  common  type  of  radiator. 
Usually  round  tubes  are  used.  To  assist  in  rapid  radiation  of  the 
heat  from  the  water  as  it  passes  down  through  the  tubes,  they  are 
mounted  in  thin  metal  vanes  or  fins.  Air  passing  over  these  fins 
cools  them  relieving  them  of  the  heat  they  receive  from  the  tubes. 
In  this  construction  the  tubes  run  from  the  top  straight  to  the  bottom. 
Tubular  radiators  are  constructed  from  fiat  tubes,  from  corrugated 


Fig.  218.    Packard  Truck  Fan  in  Section. 


Fig.  219. 


Packard   Truck  Engine  Water 
Pump  io  Section. 


tubes,  and  tubes  of  many  styles.  In  some  cases  they  are  straight 
and  in  others  they  are  bent  into  such  shape  that  when  mounted  they 
resemble  the  honeycomb  but  are  not  true  honeycomb  types. 

Honeycomb  or  Cellular  Type. — This  type  is  of  more  delicate 
construction,  is  more  expensive,  and  generally  considered  a  little  more 
efficient.  Tubes  of  round,  square,  or  hexagonal  cross  section,  are 
mounted  in  a  core  with  the  cells  a  slight  distance  apart,  the  ends 
opening  towards  the  front  and  rear  of  the  radiator.     The  air  passes 


Cooling  Systems  )199 

through  the  tubes  or  cells,  while  the  water  is  passed  around  them  in 
its  flow  from  the  top  to  the  bottom  of  the  radiator.  In  the  tubular 
type  the  water  passes  through  the  tube  and  the  air  around  it,  or  just 
the  reverse  of  the  honeycomb  or  cellular. 

Radiator  Troubles. — As  a  rule,  the  apprentice  or  mechanic  is  not 
required  to  make  more  than  minor  repairs  on  a  radiator.  He  should 
feel  no  hesitancy  in  making  the  repairs,  such  as  soldering  a  super- 
ficial break  or  a  loose  overflow  tube  or  making  any  repairs  where  the 
trouble  is  easily  reached.  Badly  damaged  radiators  should  be  turned 
over  to  the  radiator  repair  expert  or  replaced  with  new  ones.  To 
make  an  efficient  repair  on  a  badly  damaged  radiator  requires  special 
appliances  and  equipment  for  doing  the  work,  as  well  as  making 
proper  tests. 

Types  of  Pumps. — Gear  pumps  similar  to  the  oil  gear  pumps, 
rotary  pumps  similar  to  the  rotary  oil  pump,  and  centrifugal  pumps 
are  used  for  circulating  the  cooling  water.  The  last  named  is  most 
generally  used.  This  pump  is  designed  on  the  same  principal  as  any 
centrifugal  pump.  The  water  is  taken  in  near  the  center  of  the  pump 
case  or  impeller  hub.  The  impeller  turning  causes  the  water  to  be 
thrown  to  its  rim,  where  another  opening  is  provided  to  permit  it  to 
escape  into  the  other  parts  of  the  circulating  system.  Advantage  is 
taken  of  the  natural  flow  of  the  water. 

Pump  Drive. — The  timing  gears  are  usually  used  to  drive  the 
pump.  The  pump  shaft  runs  through  the  pump  case  to  the  distri- 
butor, generator,  or  whatever  other  units  of  equipment  it  is  desired 
to  drive.  The  Oakland  deviates  from  this  practice  by  driving  the 
pump  with  the  fan  belt. 

Pump  Troubles. — As  a  rule  a  pump  gives  little  trouble,  but  the 
packing  nuts  on  the  shaft  are  in  need  of  care  to  prevent  them  from 
leaking.  It  is  good  practice  to  place  a  grease  cup  on  each  pump 
bushing,  or  bearing,  in  which  graphite  grease  or  cup  grease  is  used. 
These  should  be  turned  up  regularly  to  keep  grease  in  the  bearings. 
If  water  starts  working  through,  rust  develops,  the  shaft  becomes 
pitted,  and  it  will  be  impossible  to  prevent  leaking  as  the  packing 
will  wear  away  as  fast  as  replaced.  When  there  are  no  turns  left  on 
the  packing  nut,  it  will  have  to  be  backed  off,  (one  is  a  right-hand 
thread,  the  other  left,  and  both  turn  oflf  counter  to  the  direction  of 
drive  of  the  shaft),  and  new  packing  substituted  for  that  worn  away. 
Replace  with  pump  packing  furnished  by  the  manufacturer,  if  pos- 
sible. If  this  is  not  available,  hempen  cord  well  graphited  and 
wrapped  on  the  way  the  nut  turns  will  make  a  more  or  less  perman- 
ent repair. 

Impeller  Troubles. — Occasionally,  after  considerable  service,  the 
pump  bushings  may  wear  away  permitting  the  impeller  blades  to 
strike  or  rub  on  the  pump  case.     This  will  cause  wearing  and  trouble 


200 


Automotive  Trade  Training 


in  time,  such  as  loosing  the  impeller  on  the  shaft.  It  will  be  necessary 
to  remove  and  rebuild  the  pump  in  a  case  of  this  nature.  A  point 
of  prime  importance  is  to  have  the  impeller  assembled  on  its  shaft 
correctly  to  throw  out,  or  pump  water. 

Cooling  Fans. — A  fan  is  mounted  just  back  of  the  radiator  core 
and  used  to  draw,  through  the  core,  the  air  needed  to  carry  away 
the  heat  radiated  from  the  water  coming  from  the  engine  jacket.  The 
fan  is  of  more  importance  when  the  car  is  standing,  with  the  engine 
Operating,   than   when   being   driven.     In   driving   the   air   is   forced 


Fig'.  220.     Stutz  Cooling  System.     Note  fan  and  fan  belt  adjustment,  also  fins  cast  on  the 
exhaust  manifold  as  an  aid  in  cooling. 

through  1)y  the  speed  of  the  car  as  well  as  the  draught  of  the  fan. 
The  fan  is  also  more  essential  on  low  and  intermediate  gear  speeds 
than  on  high. 

Fan  Care. — Other  than  keeping  properly  lubricated  and  belt  tight, 
little  attention  need  be  given  the  fan.  If  ball  bearings  or  roller  bear- 
ings are  used,  a  few  drops  of  oil  every  thousand  miles  will  suffice. 
If  bronze  bushings  are  used  the  grease  cups  will  need  to  receive  the 
same  attention  as  other  grease  cups. 

Fan  Belts.  —  Since  flexible  drive  is  used  on  fans,  the  proper 
tension  must  be  kept  on  the  belt.  Too  loose  permits  too  much 
slippage,  while  too  tight  prevents  any  slippage  and  causes  wear  on 
bushings  if  these  are  used  on  bearings.  A  fan  delivers  most  air  at 
certain  fixed  speeds  and  not  a  corresponding  amount  always  with 
the  increase  of  speed.     For  instance,  the  Liberty  Motor  gives  most 


Cooling  Systems 


201 


power  at  1800  R.  P.  M.,  the  propeller  gives  most  power  at  1400 
R.  P.  M.  This  leads  to  the  use  of  reduction  gears  to  obtain  the 
proper  working  speed  for  each.  Some  manufacturers  introduce  a 
friction  joint  in  the  hub  of  the  fan  to  permit  of  some  automatic  adjust- 
ment of  the  speed  to  the  power.  A  loose  or  broken  fan  belt  will 
permit  the  engine  to  become  overheated  and  a  steaming  radiator  is 
sometimes  the  result.     Tighten  or  replace  with  a  new  belt. 

Fan  Belt  Adjusting. — An  adjustment  for  the  fan  belt  is  always 
provided ;  loosening  the  set  screw  and  swinging  the  eccentric  arm 
until  proper  tension  is  obtained,  then  resetting  the  screw  is  all  that 
is  needed  to  take  up  the  belt  slack.  In  placing  on  a  new  belt,  pro- 
vision should  be  made  for  future  tightening. 

Changes  of  Temperature. — If  the  car  was  always  operated  at  a 
fixed  engine  speed  with  the  temperature  of  the  surrounding  atmos- 
phere always  at  a  fixed  point,  it  would  be  a  comparatively  simple 
engineering  feat  to  de- 
sign cooling  apparatus 
which  would  keep  the 
motor  at  just  the  proper 
temperature  for  efficient 
operation  (170  degrees 
Fahrenheit).  Since  the 
temperature  of  the  at- 
mosphere, which  is  the 
real  cooling  medium, 
varies  as  much  as  130 
degrees  Fahrenheit  at 
diflferent  seasons  of  the 
year,  in  some  communi- 
ties, it  is  necessary  for  the 
designer  to  provide  for 
the  average  temperature, 
and  to  arrange  special 
features  to  take  care  of 
extremes,  especially  ex- 
treme low  temperatures. 

In  the  summer  it  is 
sufficient  to  have  the  fan 
belt  properly  adjusted, 
radiator  properly  filled, 
ventilating  shutter  and 
covers  open.  'I-n  some 
extreme  cases  remove  part  of  the  hood  or  floor  boards,  in  case  of 
truck  engines  give  them  every  possible  chance  for  cooling. 

In  the   winter,  however,  provisions   must  be   made  tr   shut  out 


Fig.  221.  Radiator  Equipped  with  Shutters  This 
permits  of  readily  controllinjr  the  heat  of  the  engine. 
A  hand  control  for  the  shutters  is  provided  on  the 
dash.  Shutters  in  Horizontal  Position  When  Wide 
Open. 


202 


Automotive  Trade  Training 


s^^^si^^sa 


^^ss^ss 


v'v.^'v^'^vvvvvv'v'v^^vv^vvr;^ 


7..J)))JJJ))j>n^ffff. 


V/y>^/y>^^y>///A 


Cro»t  Section  Thermoitat   Arrangement.      A,  Radiator  coupling;   B,   B]r*paM 
coupling;  C,  Pi*ton  valTes;  D,  Themottat;  E,  By-pas*  teat. 

Fig.  222.     Diagram   of  Thermostat  mechanism. 

some  of  the  cold  air,  and  in  come  cases  to  control  the  circulation  of 
the  water. 

Hood  and  Radiator  Covers. — In  some  cases  manufacturers  are 
providing  a  ventilating  shutter  for  the  hood,  which  may  be  controlled 
either  by  a  thermostat  or  a  dash  control.  The  Hudson  is  a  good 
example. 

Thermostat  Control. — In  other  cases  manufacturers  are  provid- 
ing thermostatic  control  of  the  w^ater  circulation:  A  thermostat  in 
the  water  pump  intake  pipe  controls  a  valve  which  permits  the  water 
to  circulate  through  the  cylinder  jackets  so  that  the  engine  is  operat- 


^^^^^^^^^^^r^ ....-.-...-..,        "^"^l^S^I 

I^^^R^^^ 

1 



*r-'      1 

Fig.  223.     Cadillac   8  Engine. 


Cooling  Systems 


203 


ing  at  the  most  favorable  temperature  at  all  times.  The  thermostat 
D  in  Fig.  222  is  made  similar  to  an  accordion  and  is  filled  with  a 
liquid  which  vaporizes  on  being  heated  to  a  certain  comparatively 
low  temperature.  The  pressure  that  this  gas  exerts  on  the  retaining 
walls  of  the  thermostat  causes  enlongation  of  it  and  this  action  in 
turn  operates  the  valve  C  which  permits  the  water  to  flow  from  the 
radiator. 

The  water  is  not  permitted  to  circulate  from  the  radiator  to  the 
engine  until  that  in  the  water  jackets  and  pumps  and  the  bypass  has 
been  brought  to  the  correct  operating  temperature.  When  this  has 
been  accomplished  the  thermostat  gradually  opens  the  passage  to  the 
radiator. 

Cooling  Solutions. — Radiators  need  but  little  care  in  the  summer 
except  occasional  drawing  off  of  water  and  flushing  out  to  prevent 
sediment  obstructing  circulation.  In  winter,  in  addition  to  this,  the 
use  of  a  non-freezing  solution  is  recommended  to  prevent  freezing 
and  consequent  injury  of  parts.  Water  alone  will  do  very  well  when 
warm  garages  are  used  providing  the  radiator  can  be  prevented  from 
freezing  while  the  car  is  in  use.    This  is  rather  difficult  unless  all  parts 

exposed  are  carefully  protected  from  cold 
drafts  of  air,  as  for  instance,  the  lower 
water  passage  from  the  radiator  which 
frequently  freezes,  due  to  the  cold  draft 
striking  it.  A  radiator  usually  freezes  on 
the  bottom  first  when  the  car  is  in  opera- 
tion, and  on  top  first  if  standing  in  a  cold 
place  for  any  length  of  time. 

Non  -  Freezing  Solutions  Recom- 
mended.— The  best  solution  to  use  is 
wood  alcohol.  Denatured  grain  alcohol 
is  second  as  it  will  require  a  greater 
quantity  than  of  the  wood  alcohol,  with  a 
corresponding  reduction  of  temperature 
of  the  solution.  Alcohol  and  glycerine  is 
ranked  perhaps  as  second  choice  after  the 
alcohols.  The  glycerine  having  a  high 
boiling  point  counteracts  the  low  boil- 
One  bad  feature  of  the  glycerine  is  its 
tendency  to  attack  rubber,  but  this  tendency  is  offset  to  a  certain 
extent  by  the  alcohol.  Glycerine  is  also  more  expensive  to  use  than 
alcohol. 

Calcium  chloride  solutions  are  very  largely  used.  They  form  the 
nearest  ideal  solution  in  point  of  reduction  of  freezing  temperature 
and  low  boiling  point,  but  there  are  several  points  which  make  their 
use  somewhat  risky.     The  solution  is  acid  by  nature  and  acids  are 


Fig.   224.     Cadillac   S   Pump. 

ing  point   of  the   alcohol 


204 


Automotive  Trade  iRAiiiiifG 


PACKIMG  hUT 


FOnP  ItlPCLLCR 


Fig.  225.     Note  Double  Bladed  Fan   Construction   and   method   of  drive. 


Cooling  Systems 


205 


known  for  their  ability  to  corrode,  eat  away  and  destroy  certain 
metals.  It  is  necessary  to  have  the  acid  neutralized  by  the  addition 
of  soda  ash  or  some  other  alkaline  substance.  When  properly  neutral- 
ized the  solution  is  not  supposed  to  be  particularly  dangerous.  To 
test,  place  a  piece  of  the  blue  litmus  paper  in  the  solution.     If  it 


Fig.  226.    Packard  Twin  Six  in  Section.     Note  fins  cast  on  bottom  of  crank  case  or  oil 
pan.     These  assist  in  keeping  the  lubricating  oil  cool. 

turns  red,  free  acid  is  present  and  more  soda  ash  should  be  added. 
A  large  number  of  brands  of  the  calcium  chloride  preparations  or 
similar  substances  are  on  the  market.  Some  are  particularly  harmful 
to  aluminum  parts,  and  if  used  in  a  cooling  system  having  an 
aluminum  pump  case  for  instance,  it  will  so  eat  it  or  pit  it  as  to  make 


206  Automotive  Trade  Training 

replacem-ent  necessary.  Manufacturers  of  this  type  of  product  are 
rather  conscientious^  and  if  directions  for  the  use  of  their  product  are 
followed,  little  trouble  need  be  expected.  It  might  be  worth  the 
student's  while  to  know,  too,  that  since  the  solution  is  acid  and  comes 
in  contact  with  metals  of  various  kinds  that  electrolytic  action  is 
likely  to  take  place,  thus  weakening  joints. 

Over  Heated  Motors. — In  order  that  the  driver  may  know  at  all 
times  that  his  engine  is  not  overheating,  various  devices  showing 
the  operating  temperature  have  been  perfected. 

Boyce  Motometer. — This  is  the  most  popular  device  for  the 
purpose.     A  thermometer  is  arranged  to  show  the  driver  the  safe 


Fig.  227.    Continental  7R.     Note  water  jackets  around  cylinder. 

operating  temperature  and  the  danger  point  as  represented  by  the 
heat  within  the  radiator.  The  danger  here  is  that  the  driver  may 
become  so  accustomed  to  the  perfect  operation  of  his  engine  that  he 
will  not  notice  a  sudden  rise  of  the  mercury  or  approach  of  the 
danger  point. 

Recognizing  An  Overheated  Motor.  —  The  careful  experienced 
driver  needs  no  special  device  to  tell  him  his  engine  is  overheating. 
His  ear  has  become  so  attuned  to  the  natural  hum  of  his  engine  that 
any  unusual  sound  is  quickly  recognized.  Overheating  will  give  rise 
to  these  unusual  sounds,  the  main  one  of  which  is  a  pounding  or 
knocking  sound,  as  in  overloading  the  motor  on  a  heavy  grade  on  a 
hot  day.  Instead  of  a  smoothly  running  sound  the  engine  seems  to 
labor,  to  give  out  a  harsh  more  grinding  sound  as  of  parts  running- 


Cooling  Systems 


207 


without  lubrication.  This  is  very  likely  to  be  true  as  the  oil  is  likely 
thinned  out  and  burned  up  due  to  the  unusual  heat.  Steaming  at  the 
radiator  filler  cap  and  the  sound  of  boiling  water  may  or  may.  not 
be  noticed. 

Causes  of  Overheating. — Hot  weather  is  perhaps  the  most  fre- 
quent cause  of  overheated  engines,  as  it  has  such  a  direct  effect  on 
the  cooling  of  the  water  in  the  radiator.  This  need  not  result  in 
burned  out  bearings  or  scored  cylinders  if  due  care  is  exercised  to 
have  the  cooling  system  in  good  condition,  as  having  the  fan  belt 
tight  and  the  radiator  cleaned  of  all  dirt  and  sediment  and  properly 


Fig.   228.     Continental  7K.     Note   Water   Pump,   Oil   Pump   and   Fan   Adjustment. 

filled ;  also  the  oiling  system  in  good  condition  and  an  oil  of  the  high 
flash  test  in  the  engine.  Needless  to  say,  the  oil  must  be  clean  and 
free  of  carbon  or  other  foreign  matter.  Refer  to  the  chapter  on  oiling 
systems  to  get  the  essential  points. 

Cooling  the  Overheated  Engine.  —  Ordinarily  the  overheated 
engine  will  be  quickly  cooled  if  the  bad  stretch  of  road  is  passed  and 
the  engine  relieved  of  its  overload,  as  topping  the  bad  hill  and  coming 
onto  a  level  stretch.  Here  the  air  rushing  through  the  radiator  will 
quickly  right  the  trouble.  This  cannot  always  be  done  as  in  pulling 
through  bad  gravel,  mud  and  sand,  or  climbing  long  heavy  grades. 
Then  it  is  best  to  allow  the  motor  to  stand  idle  until  the  water  has 
had  a  chance  to  cool  off  the  engine.  Raising  or  removing  the  hood 
will  always  help. 

Filling  An  Overheated  Engine. — In  the  overheated  engine  the 
water  in  the  radiator  may  have  boiled,  away  so  that  it  will  need  refill- 


208  Automotive  Trade  Training 

ing.  The  great  danger  here  is  that  the  sudden  introduction  of  cold 
water  on  cylinder  walls,  heated  to  a  red  hot  heat  in  some  cases,  may 
cause  them  to  suddenly  contract  and  crack,  thus  making  their  replace- 
ment necessary.  If  there  is  any  likelihood  that  the  water  is  all  gone 
from  the  cylinder  blocks,  time  must  be  given  to  allow  the  extreme 
heat  to  be  radiated  and  then  water  added  very  slowly. 

Non-Leak  Solutions. — The  radiator  being  made  up  from  so  many 
thin  parts  and  subjected  to  constant  jars,  hammering,  twisting,  and 
straining,  small  leaks  are  likely  to  develop.  These  are  likely  to  occur 
in  either  new  or  old  radiators  and  often  are  in  places  very  hard  to 
reach  to  repair  with  the  soldering  iron.  It  is  sometimes  advisable  to 
use  a  non-leak  solution  in  the  radiator.  All  serious  leaks  should  be 
soldered  if  the  repair  is  to  be  made  permanent. 

Use  of  Cereal  Preparations. — Plain  cereals  such  as  corn  meal, 
ground  flax  seed,  bran,  etc.,  will  serve  as  a  temporary  repair  even  in 
a  rather  serious  leak  and  a  knowledge  of  the  fact  may  enable  the 
driver  to  get  out  of  a  very  trying  situation.  The  practice  is  to  be 
discouraged  as  a  general  thing  since  'the  excess  will  settle  in  the 
radiator,  or  in  the  water  jacket,  and  tend  to  obstruct  circulation  and 
radiation.  These  cereals  clog  the  leak  because  in  attempting  to  pass 
through  they  are  caught  and  as  the  water  affects  them  they  are 
swelled  to  fill  the  opening. 

Use  of  Liquid  Preparations. — The  liquid  preparations  may  be 
recommended  more  highly.  X  liquid  (a  trade  name)  is  a  good 
example.  It  is  placed  in  the  radiator  with  the  water.  The  solids  in 
it  remain  in  solution  indefinitely,  unless  they  are  carried  p\xt  or 
steamed  out  through  the  leak,  when  they  are  left  in  it,  or  on  it  as  a 
hard  insoluble  deposit.  In  a  short  time,  ten  or  twenty  minutes,  the 
leak  will  be  sealed.  To  facilitate  the  heating  of  the  water  it  is  well 
to  cover  the  radiator  for  a  time.  This  solution  cleans  the  radiator 
of  scale  and  is  claimed  to  be  beneficial  in  this  respect. 

Cleaning  the  Radiators. — All  radiators  must  be  flushed  out 
occasionally.  A  strong  alkali  such  as  soda  will  remove  scale  and 
tend  to  seal  small  leaks. 

JOB  76.     RADIATOR  HOSE  CARE. 

The  radiator  hose  connections  are  very  frequently  the  source  of  trouble. 
Leaks  develop  around  the  hose  bands  and  the  rubber  disintegrates  on  the 
inside  stopping  the  flow  of  the  water. 

1.  To  stop  a  leak  about  the  hose,  use  a  screwdriver  to  draw  the  clamp 
bolt  tighter. 

2.  Failing  this,  it  may  be  necessary  to  renew  the  clamp  if  it  should  be 
found  in  poor  condition. 

3.  The  hose  itself  may  be  rotten  or  broken  in  such  manner  that  it  must 
be  renewed. 

4.  If  the  hose  is  in  good  condition,  and  drawing  on  a  clamp,  likewise  in 
good  condition,  fails  to  stop  the  leak,  shellac  may  be  resorted  to.     Remove  the 


Cooling  Systems  209 

hose.     Coat  the  inlet  with  shellac  and  allow  same  to  dry  until  tacky.     Replace 
hose  and  tighten. 

4.  Where  the  hose  must  be  replaced  the  first  step  is  to  release  the  clamp. 

5.  Grasp  the  hose  in  the  hand  and  give  a  good  pull  and  twist  at  the  same 
time.  If  this  will  not  loosen  it  the  screwdriver  blade  may  be  used  to  run  under 
the  hose  and  thus  work  it  loose. 

6.  Whenever  the  hose  shows  signs  of  breaking  out  on  the  inner  lining  or 
rubber  it  should  be  discarded. 

7.  In  fitting  the  new  hose  it  is  not  shellaced  unless  this  is  found  the  only 
means  of  stopping  a  leak. 

8.  Be  very  certain  to  avoid  any  kinks  in  the  new  piece  of  hose  as  it  is 
applied.  A  kink  interferes  with  the  ready  passage  of  the  water.  Particular 
care  must  be  used  to  keep  the  passages  free. 

9.  In  adjusting  the  fan  be  very  certain  that  the  blades  do  not  come  into 
contact  with  the  rubber  hose.  Sometimes  a  fan  adjustment  fails  and  the  hose 
is  cut  by  the  blades. 

10.  It  is  a  good  plan  to  change  the  hose  at  least  once  each  year. 

JOB  77.     RADIATOR  CARE. 

Since  the  water  passages  in  the  radiator  are  very  small,  it  is  quite  essential 
that  they  be  kept  open.  The  use  of  any  water  bearing  such  matters  as  lime 
m  solution  will  lead  to  a  partial  stoppage  of  the  passages  and  overheating  of 
the  engine.  To  remove  sediment  collections  it  is  well  to  flush  out  the  radiator 
at  least  once  each  season  and  preferably  every  month  or  so.  To  do  this 
proceed  as  follows: 

1.  Place  the  car  on  the  washstand,  or  elsewhere,  where  the  water  may 
flow  from  the  radiator  and  be  carried  off  properly. 

2.  Start  the  engine  running  at  a  moderate  speed. 

3.  Open  the  drain  cock. 

4.  Place  the  end  of  the  hose  in  the  radiator  and  turn  on  the  water.  Allow 
the  water  to  run  into  the  top  of  the  radiator  just  a  trifle  faster  than  it  runs  out 
of  the  pet  or  drain  cock.  The  overflow  tube  will  care  for  this  trifle  of  excess 
and  the  water  need  not  run  over  the  outside  of  the  radiator. 

5.  Allow  the  water  to  run  with  the  engine  running  for  from  15  to  30 
minutes. 

JOB  78.     REMOVING  A  RADIATOR. 

1.  Drain  the  water.  If  a  non-freeze  solution  is  in  use,  save  the  solution 
for  refilling. 

2.  Remove  the  engine  hood. 

3.  Remove  the  stay  rod  if  there  is  one. 

4.  Loosen  the  radiator  bolts  where  the  radiator  shell  is  fastened  to  the 
frame  of  the  car. 

5.  Loosen  the  radiator  hose  bands. 

6.  Make  certain  that  the  radiator  hose  is  loosened  from  the  water  inlets 
on  the  radiator. 

7.  Lift  oflf  the  radiator. 

8.  If  it  is  desired  to  remove  the  radiator  from  the  shell,  this  is  done  by 
removing  the  small  bolts  used  in  most  cases  to  hold  the  two  together. 

JOB  79.     TESTING  A  RADIATOR  FOR  LEAKS. 

1.  Remove  radiator.     (Job  78.) 

2.  Solder  a  piece  of  brass  or  other  sheet  metal  over  each  of  the  outlets. 
(Hose  connection  pipes  and  overflow  tubes.) 

3.  Fill  with  water.     Turn  on  radiator  cap. 


210  Automotive  Trade  Training 

4.  Using  a  foot  pump  with  air  line  slipped  on  over  the  drain  cock,  force 
in  a  slight  pressure  of  air.     Not  over  five  pounds  pressure  should  be  used. 

5.  This  will  cause  the  water  to  run,  or  in  cases  of  a  decided  leak,  to  be 
sprayed  out  from  the  points  where  the  radiator  is  leaking. 

6.  Locate  the  several  leaks  and  mark  their  position  after  which  the 
radiator  is  soldered. 

SECOND  METHOD. 

1.  Place  the  radiator  with  all  the  outlets  soldered  shut  into  a  trough  or 
tub  of  water. 

2.  Force  air  at  a  pressure  of  not  to  exceed  five  pounds  into  the  radiator 
noting  the  points  at  which  the  bubbles  arise  and  marking  them  for  repair  by- 
soldering. 

3.  In  the  case  of  a  bad  leak  there  may  be  no  need  of  following  either  of 
the  above  methods  as  the  leak  is  easily  located  before  removing  the  radiator 
from  the  car. 

4  After  repairing,  either  of  the  above  tests  may  be  applied  to  learn  the 
condition  of  the  job. 

5,  If  there  is  time,  the  radiator  should  be  filled,  placed  in  an  upright 
position  and  left  over  night  to  learn  whether  or  not  the  repair  is  complete. 

JOB  80.     REPAIRING  A  RADIATOR  LEAK  WITH  A  LIQUID 

COMPOUND. 

The  liquid  preparations  on  the  market  for  use  in  repairing  radiators  are 
all  similar  in  nature.  They  are  placed  in  the  radiator  and  as  they  are  steamed 
through  the  leaks  they  solidify  on  coming  into  contact  with  the  air.  They  are 
safe  to  use.     X-Liquid  is  a  sample  of  this. 

1.  Drain  and  flush  the  radiator  as  recommended  in  Job  77. 

2.  Fill  the  radiator  within  a  quart  of  full,  using  clean  soft  water. 

3.  Start  the  engine  running.  Make  certain  that  the  oil  m  the  crankcase  is 
up  to  the  "full"  mark. 

4  Throw  a  blanket  over  the  radiator  leaving  the  filler  cap  off  and  the 
filler  tube  exposed  so  as  to  note  when  the  water  comes  to  the  boiling  and 
steaming  pomt 

5.     Put  in  the  required  amount  as  directed  on  the  container. 

6  Continue  to  operate  the  motor  until  the  radiator  shows  dry  under  the 
blanket  This  is  possible  because  of  the  fact  that  as  the  leaks  are  sealed  the 
watei  ceases  to  seep  through.  Any  water  on  the  radiator  is  quickly  dried  off 
due  to  the  fact  that  the  water  on  the  inside  of  the  radiator  is  at  the  boiling 
point.  Since  the  action  of  the  compound  is  dependent  on  the  heat,  it  is  just 
as  well  and  perhaps  better  to  do  the  work  on  the  floor  where  the  temperature 
ot  the  engine  may  be  watched  than  it  is  to  attempt  to  do  it  on  the  road  when 
the  engine  may  or  may  not  reach  the  required  temperature.  If  the  engine  is 
held  at  that  speed  which  will  just  boil  the  water  and  the  proper  amount  of  oil 
supplied  to  it  there  is  no  danger  ot  burning  it  out 

JOB  81      REPAIRING  A  RADIATOR. 

1.  Remove  and  test  the  radiator  as  indicated  in  Jobs  78  and  79. 

2.  Solder  all  the  leaks  appearing  on  the  outer  surfaces  and  about  the 
reservoirs  and  overflow  tubes.  This  work  is  readily  done  with  the  regular  iron. 
Treat  the  parts  with  soldering  salts  or  acid.  If  the  solder  refuses  to  take,  , 
wipe  the  part  while  still  hot  with  a  rag  saturated  with  the  acid.  Continue 
heating  and  treating  the  parts  until  the  solder  does  take.  Of  course,  the  major 
part  ot  the  dirt  and  corrosion  is  scraped  from  the  parts  before  attempting  to 
solder  them,  but  even  then  difficulty  is  frequently  experienced  in  getting  the   ■ 


Cooling  Systems  211 

solder  to  take  and  run  properly.     The  acid  steamed  off  the  hot  part  will  be  of 
material  help. 

3.  The  soldering  of  the  leaks  on  the  inner  parts  of  the  core  or  tubes  is  an 
operation  requiring  skill  and  patience.  Very  frequently  the  large  iron  will  not 
reach  the  point  where  the  leak  is.  In  such  a  case  the  workman  must  devise 
other  means  of  bringing  the  heat  to  the  point  where  it  is  needed. 

4.  A  lead  burning  flame  will  do  the  work  in  some  cases. 

5.  A  safer  method  for  the  small  leak  is  to  use  a  piece  of  copper  rod  of  a 
size  suitable  to  get  to  the  leak  and  make  of  it  a  soldering  iron.  In  some 
instances  the  work  can  be  hastened  by  using  the  lead  burning  or  other  flame 
on  the  outer  end  of  this  small  rod,  the  heat  then  being  conducted  to  the  point 
through  the  rod.  This  does  away  with  the  trouble  experienced  in  having  the 
rod  cooled  so  rapidly  that  the  solder  cannot  flow. 

6.  In  the  case  of  certain  cells  of  the  cellular  type  leaking,  it. is  sometimes 
possible  to  make  a  repair  by  soldering  a  small  piece  of  sheet  metal  over  each 
end  of  the  cell.  This  is  a  repair  recommended  only  for  very  old  radiators  or 
for  temporary  repair  to  hold  until  the  repair  can  be  brought  to  a  radiator 
expert. 

7.  As  a  rule  the  radiator  work  of  a  serious  nature  should  be  left  to  the 
mechanic  and  shop  well  fitted  and  equipped  for  this  class  of  work.  The  auto 
mechanic  should  attempt  only  those  jobs  which  are  rather  easily  reached. 

JOB  82.     OVERHAULING  A  WATE^  PUMP. 

It  very  frequently  happens  that  failure  of  the  ,coaling  system  can  be  traced 
to  the  failure  of  the  water  pump.  Where  the  p|iimp  is  suspected  proceed  as 
follows:  •  '.r 

1.  Remove  the  pump  from  the  engine. 

2.  Take  it  to  the  bench  and  open  it  up.  Use  care  in  this  operation,  noting 
carefully  the  proper  relation  of  parts.  In  working  on  a  water  pump,  difficulty 
is  frequently  experienced  with  screw  threads  due  to  the  fact  that  the  water  has 
rusted  them.  Unless  care  is  utilized,  it  is  quite  possible  to  have  the  set  screws 
broken  off  in  thecastings. 

3.  Inspect  all  parts  for  wear,  particularly  the  impeller.  If  this  is  worn 
considerably  at  points  where  it  comes  into  contact  with  the  case  it  should  be 
replaced. 

4.  Inspect  the  shaft  to  see  if  the  water  has  pitted  and  rusted  it.  Replace 
if  necessary. 

5.  Inspect  the  shaft  bearings  which  are  of  the  bronze  metal  type  in  most 
instances.     If  worn  badly,  replace. 

6.  If  the  pump  is  generally  in  bad  condition  the  entire  unit  should  be 
replaced  with  a  new  one.  Aluminum  pump  cases  are  particularly  subject  to  the 
action  of  certain  non-freeze  solutions  which  cause  the  inside  of  the  pump  to 
be  eaten  away  in  an  alarming  fashion.  The  same  is  true  of  certain  water 
supplies  in  which  impurities  are  found. 

7.  The  most  frequent  pump  trouble  is  the  loosening  of  the  impeller  on 
the  pump  shaft.     Make  this  secure  in  reassembling  the  job. 

8.  Reassemble  and  replace  the  pump  on  the  engine. 

9.  Test. 

JOB  83.     PACKING  A  PUMP. 

The  pump  shaft  very  frequently  runs  through  both  sides  of  the  pump  case 
and  is  supplied  with  two  packing  nuts  or  bushings.  These  must  be  maintained 
in  proper  condition  to  prevent  leaking. 

1.  Fig  229  shows  the  National  Sextet  engine  and  pump.  Directions  are 
also  given  for  tightening  the  nuts. 


212 


Automotive  Trade  Training 


2.  The  nuts  are  always  tightened  by  turning  them  in  the  direction  of 
rotation  of  the  pump  shaft. 

3.  When  the  nuts  have  been  turned  all  the  way  into  the  case  they  will 
perhaps  no  longer  retain  all  of  the  water.  In  this  case  they  will  need  to  be 
repacked.  It  is  better  to  repack  than  to  attempt  to  force  the  nut  a  bit  farther. 
This  is  likely  to  result  in  a  broken  pump  shaft  housing. 

4.  Back  off  the  packing  nuts. 


Fig.   229.    Packing   a   National   Sextet  Pump. 

5.  Secure  the  proper  pump  packing  from  the  car  manufacturer,  or  failing 
this  use  some  felt  or  woolen  yarn  to  wrap  the  shaft  with.  Even  hempen  or 
cotton  string  may  be  used,  although  any  packmg  to  give  the  best  service  must 
not  be  too  hard.     Use  graphite  grease  to  pack  the  packing  in. 

6.  Turn  the  new  packings  down  snugly. 

7.  Operate  the  engine  and  then  give  the  packing  nuts  a  further  turn. 

8.  See  that  the  grease  cups  are  properly  filled  and  turn  them  down  until 
grease  starts  oozing  from  the  packing  nut.  If  no  leaks  show,  this  should 
complete  the  job. 


CHAPTER  9 
FUEL  SYSTEMS 

GASOLINE  SYSTEMS 

There  are  three  types  of  gasoline  systems  in  general  use.  These 
are  the  gravity,  pressure  and  vacuum.  This  applies  more  especially 
to  the  method  of  bringing  gasoline  to  the  carburetor  from  the  main 
supply  tank.  More  recently,  however,  the  term  gasoline  system  has 
come  to  mean  all  methods  and  units  or  parts  used  in  storing,  feeding 
and  supplying  the  fuel  to  the  engine  ready  to  be  compressed. 

Gravity  System. — This  system  was  formerly  used  very  exten- 
sively on  both  trucks  and  passenger  vehicles.  The  vacuum  system 
has  largely  replaced  it  for  passenger  car  use.  For  this  system  to 
work  satisfactorily  it  is  necessary  that  the  supply  tank  be  placed  at 
a  point  considerably  higher  than  the  carburetor.  As  gasoline  is 
drawn  from  the  carburetor,  more  is  permitted  to  flow  from  the 
supply  tank  to  the  carburetor  bowl  through  the  feed  line.  The  tank 
is  either  carried  on  the  dash  under  the  front  seat,  or  on  the  deck  as 
in  the  case  of  the  roadster  or  speedster.  The  supply  tank  in  this 
case  need  be  only  of  medium  strong  construction.  The  cover  must 
always  be  provided  with  a  vent  to  permit  air  to  enter  as  gasoline 
flows  out  to  the  carburetor.  This  vent  must  be  of  such  a  nature  as 
to  prevent  the  gasoline  being  splashed  out. 

This  system  is  pretty  certain  to  require  a  low  hung  carburetor 
and  a  long  intake  pipe,  especially  so  where  the  tank  is  placed  under 
the  seat.  In  the  case  of  the  tank  under  the  cowl  it  has  the  disad- 
vantage of  having  the  tank  immediately  in  front  of  the  driver  and 
very  close  to  the  engine.  This  is  likely  to  result  in  poor  body  design. 
The  fumes  from  the  gasoline  are  frequently  annoying  to  passengers. 
Dirt  and  grease  will  accumulate  about  the  tank  due  to  frequent  fill- 
ings. Since  the  instrument  board  is  always  located  on  the  cowl  the 
tank  under  the  cowl  makes  the  adjustment  of  the  wiring  and  instru- 
ments rather  difficult.  The  great  advantage  is  the  short  feed  line 
and  the  ease  with  which  any  trouble  within  the  feed  line  is  located. 

Pressure  Feed. — This  requires  the  gas  tank  to  be  heavy  enough 
to  resist  or  withstand  a  light  pressure.  No  vent  is  provided.  On 
the  contrary,  the  tank  must  be  sealed  air  tight  to  prevent  the  air 
pumped  into  it  escaping.  A  pump  operated  by  the  engine  when  it 
is  running  is  provided  to  keep  the  pressure  in  the  supply  tank  up  to  a 
point  where  the  gasoline  flows  to  the  carburetor  as  it  is  used.  A 
hand  pump  is  used  to  provide  initial  pressure  in  starting  after  the 
car  has  stood  a  time,  or  if  for  any  reason  the  gasoline  level  falls  too 

213 


214 


Automotive  Trade  Training 


low  in  the  carburetor.  This  would  be  the  case  if  the  tank  was  not 
sealed  properly,  if  the  automatic  pump  failed,  or  the  carburetor  was 
drained.  Since  the  tank  in  the  pressure  feed  is  carried  in  the  rear, 
one  serious  disadvantage  has  always  been  the  number  of  long  air 
lines  and  gasoline  feed  lines  to  keep  in  repair.  The  two  pumps  are 
also  likely  to  give  trouble  and  the  tank  is  hard  to  keep  tightly  sealed. 
Vacuum   Systems. — This   system   is   used   almost   altogether   for 


;:iid^^^|H 

fiHf 

TO^ 

^mU 

'mm^ 

^EhI 

|j(r  r 

VRpP 

'1 

1 

Fjff.    230,     Packard    Liberty    Aeroplane   Motor    Equipped    with    Fuelizer. 

passenger  car  work  and  in  a  large  number  of  commercial  cars.  The 
supply  tank  is  placed  on  the  rear  end  of  the  chassis,  while  the  vacuum 
tank  is  placed  under  the  hood  on  the  dash  or  on  the  engine.  Gasoline 
is  fed  by  gravity  from  the  vacuum  tank  to  the  carburetor.  It  is 
drawn  from  the  supply  tank  to  the  vacuum  tank.  The  supply  tank 
is  carried  on  the  rear  of  the  chassis  and  must  be  lower  than  the 
vacuum  tank.  This  system  utilizes  the  best  features  of  each  of  the 
other  systems.  One  disadvantage  is  the  number  of  air  and  gas  lines 
to  be  kept  free  and  in  service. 


Fuel  Systems 


215 


Vacuum  Tank. — The  vacuum  tank  is  so  designed  as  to  auto- 
matically lift  the  gasoline  from  the  supply  tank  to  the  vacuum  tank. 
A  small  supply,  about  half  a  gallon,  is  carried  in  the  vacuum  tank, 
from  which,  as  stated,  it  is  fed  to  the  carburetor  as  needed. 

For  the  student  to  grasp  the  action  of  the  vacuum  tank  it  is 


Fig.   231.    Packard   Twin   Six   Pressure   Peed   Gasoline   System. 

necessary  that  he  understand  the  vacuum  principle.  It  is  commonly 
said  that  nature  abhors  a  vacuum.  That  is,  nature  seems  to  make 
provision  that  if  one  element  is  withdrawn  or  removed  from  a  certain 
space  or  place  another  element  is  always  on  hand  ready  to  move 
into  the  place  vacated.  This  may  be  observed  in  relation  to  water. 
Suppose  a  brick  is  placed  in  a  pail  and  covered  with  water.  Remov- 
ing the  brick  does  not  leave  a  hole  in  the  water,  rather  the  space 
occupied  by  the  brick  is  filled  immediately  by  the  water.  However, 
if  the  water  did  not  fill  the  space  and  no  air  were  permitted  to  enter 
to  fill  the  place  a  vacuum  would  be  the  result.  Again,  a  dipper  may 
be  used  to  remove  part  of  the  water  from  the  pail.  Neither  does  this 
cause  a  vacuum  as  air  immediately  rushes  in  to  fill  the  space  formerly 
filled  by  the  water.  Having  these  things  in  mind,  it  will  be  easier 
to  grasp  the  action  of  the  vacuum  tank  which  is  dependent  on  a 
natural  law  for  its  unfailing  response  under  all  conditions. 

The  upper  part  of  the  vacuum  tank  is  connected  with  the  intake 
manifold  of  the  engine  as  may  be  seen  in  the  cut  showing  the  Reo 
gasoline  system,  Fig.  232.  As  the  piston  travels  down  in  the  cylinder 
on  the  intake  stroke,  a  suction  is  created  which  draws  air  out  of  the 
upper  chamber  of  the  tank.  Since  thevf'air  from  the  outside  cannot  en- 
ter the  vacuum  tank  due  to  the  air  va|vve  being  held  closed,  a  vacuum 
is  formed  or  a  place  in  which  there  is  neither  air  or  gasoline.  No  air 
can  enter  the  tank  except  through  the  main  supply  tank  and  here 
all  the  gasoline  must  be  forced  out  of  the  way.     In  attempting  to 


216 


Automotive  Trade  Training 


Fuel  Systems 


217 


enter  the  vacuum  tank  through  the  gasoline  supply  tank  the  gasoline 

IS  carried  ahead  of  the  air.     If  no  more  gasoline  is  placed   in  the 

supply  tank  the  air  will  eventually  succeed  in  getting  to  the  vacuum 

tank,  but  only  after  the  gasoline  has  all  been  forced  up  to  the  vacuum 

tank,  or  after  the  gasoline  is  all  used.     As  the  gasoline  is   carried 

into  the  vacuum  tank  it  first  fills  the  upper  chamber  and  then  flows 

into  the  lower  chamber.     When  both  chambers  have  the  proper  level 

of  gasoline  in  them  the  float  rises  to  cut  off  the  suction  from  the 

cylinder.     At  the  same  time  the  air  valve  or  vent  to  the  upper  tank 

is  opened  which  action  permits  the  gasoline  to  feed  to  the  lower  tank. 

This  lower  chamber  is  always  vented  through  the  curved  vent  pipe. 

This  arrangement  insures  a  supply  of  gasoline  to  the  carburetor  while 

the  upper  tank  is  filling.     However, 

as  the  gasoline  flows  from  the  upper 

chamber  to  the  lower  chamber,  the 

float   falls   with   the   gasoHne   level. 

At  a  predetermined  point  the  spring 

together  with  the  float  action  causes 

the  air  valve  on  the  upper  tank  to 

close   and   the   suction   valve   to   be 

reopened,     thus     permitting     more 

gasoline    to    flow    into    the    upper 

chamber.    The  above  operations  are 

continually  being  repeated.     While 

the  engine  is  running  and  gasoline 

is  being  used,  the  operations  occur 

at  rather  regular  intervals,  the  action 

being    automatically    controlled    by 

the  rise  and  fall  of  the  float  within 

the   upper   chamber.     The   Stewart 

vacuum    tank    is    illustrated.      All 

vacuum    tanks   work   on    the    same 

principle. 

Stewart  Vacuum  Tank  Parts. — 
Figs.  233,  234  and  235  illustrate  the 
Stewart  vacuum  tank  in  section 
and  in  detail.  A  careful  study  of 
the  illustrations  and  the  text  will 
give  the  student  or  mechanic  a  clear 
idea  of  the  manner  in  which  it  op- 
erates. 

A  is  the  suction  valve  for  opening  and  closing  the  connection  to 
the  manifold,  and  through  which  a  vacuum  is  extended  from  the 
engine  manifold  to  the  gasoline  tank. 

B  is  the  atmospheric  valve  and  permits  or  prevents  an  atmos- 


Fig.  233. 


Stewart  Vacuum  Tank  in 
Section. 


218 


Automotive  Trade  Training 


pheric  condition  in  the  upper  chamber.     When  the  suction  valve  A 
is  open  and  the  suction  is  drawing  gasoHne  from  the  main  reservoir, 

the  valve  B  is  closed.  When  valve 
A  is  closed  then  valve  B  must  be 
open  as  an  atmospheric  condition 
must  be  present  in  the  upper  tank 
to  allow  gasoline  to  flow  through 
the  flapper  valve  into  the  lower 
chamber. 

C  is  the  pipe  connecting  the 

tank  to  the  manifold  of  the  engine. 

D   is  the   pipe  connecting  the 

vacuum  tank  to  the  main  gasoline 

supply  tank. 

E  is  the  lever  to  which  the 
two  coil  springs  are  attached.  This 
lever  is  operated  by  the  movement 
of  the  float  G. 

F  is  the  short  lever  which  is 
operated  by  the  lever  E,  and  which 
in  turn  operates  the  valves  A 
and  B. 

G  is  the  float  which  operates 
the  valve  mechanism  as  it  rises 
and  falls  with  the  gasoline  level. 

This     flapper     valve   .is,    held 
closed  by  the  action  of  the  suction 
whenever  valve  A  is  open.     How- 
ever,    it    is  forced     open     by    the 
weight  of  the  gasoline  when  the  float  valve  has  closed  valve  A  and 
opened  valve  B. 

A  petcock  for  drawing  water  or  sediment  out  of  the  reservoir  is 
provided.  It  may  also  be  used  for  drawing  off  a  small  quantity  of 
gasoline  for  priming  the  engine  or  for  other  uses. 

A  line  to  the  carburetor  is  extended  on  the  inside  of  the  tank 
to  form  a  pocket  for  trapping  water  and  sediment. 

A  channel  space  is  provided  between  the  inner  and  outer  shells 
which  connects  with  the  air  vent,  thus  admitting  an  atmospheric  condi- 
tion in  the  lower  chamber  at  all  times.     This  is  necessary  to  permit 
of  an  even  flow  of  fuel  to  the  carburetor  at  all  times. 
M  is  the  guide  for  the  float. 
N  is  the  vacuum  check  valve. 

P  is  a  pipe  line  leading  to  the  vacuum  pump  on  the  dash.  This 
is  not  always  provided.  It  is  very  useful  for  priming  the  vacuum 
tank  should  it  for  any  reason  become  empty.     It  is  not  necessary  to 


Fig.  234.     Float  and  valve  mechanism  of 
Stewart   Vacuum   Tank, 


Fuel  Systems 


219 


GASOLINE 
INLET 


f     OUTLET  OR 
"FLAPPER 
VALVE 


TO 
PFilMER  PUMP 


DRAIN 


TO 

Vacuum  pump 


AIR  VENT 


AIR  RELIEF 
VALVE 


TO 
ARBURETOR 


Fig.  235.    Stewart  Vacuum  Tank  Operation. 


220  Automotive  Trade  Training 

turn  over  the  engine,  but  merely  to  pull  the  plunger  in  the  vacuum 
pump  two  or  three  strokes  which  will  create  sufficient  vacuum  or 
suction  to  draw  gasoline  from  the  main  supply  tank. 

R  is  an  air  vent  over  the  atmospheric  valve.  It  also  provides 
the  opening  to  permit  air  entering  the  lower  chamber  as  described 
on  page  218. 

PRINCIPLES  OF  CARBURETION 

The  act  of  charging  air  with  a  supply  of  fuel  (gasoline)  is  called 
carbureting  or  carburetion.  The  instrument  provided  for  maintain- 
ing the  proper  mixture  at  all  engine  speeds  is  called  a  carburetor. 
The  student  must  understand  the  principles  of  vaporization  to  under- 
stand carburetion,  as  it  is  only  when  the  fuel  is  vaporized  that  it  can 
be  mixed  with  or  incorporated  in  the  air  as  a  fuel  charge  which  is  an 
explosive  mixture. 

Evaporating  Liquids. — A  great  many  liquids  may  be  evaporated 
and  caused  to  float  in  the  air.  Water  vapor  may  be  seen  leaving  a 
river  or  lake  on  cold  mornings.  Fog  is  water  vapor  visible  to  the 
eye.  Steam  is  a  water  vapor  visible  to  the  eye  when  first  released 
into  the  air.  It  is  visible  for  only  a  short  time,  however,  although 
it  still  remains  suspended.  Setting  a  pan  of  water  in  the  air  will 
cause  evaporation  to  start  immediately  which  process  continues  until 
all  water  is  gone  or  evaporated  from  the  pan.  The  vapor  coming 
off  is  not  visible  to  the  eye,  but  does  continue  steadily,  as  regular 
measurements  will  show. 

Clothes  hung  on  the  line  dry  rapidly  because  the  water  Is 
evaporated  quickly  when  large  surfaces  are  exposed  to  the  air.  if 
the  sun  is  shining  the  heat  from  it  will  greatly  assist  in  drying 
them.  The  evaporating  process  is  always  hastened  by  heat.  On  the 
other  hand,  the  sun  may  not  be  shining  but  the  wind  blowing,  in 
which  case  the  action  is  again  hastened.  Clothes  dry  faster  in  sum- 
mer than  in  winter  due  to  the  greater  amount  of  heat,  likewise  more 
quickly  when  more  air  is  brought  in  contact  with  them.  However, 
the  clothes  may  be  frozen  stiff  almost  immediately  on  being  hung 
on  the  line  in  the  winter.  This  does  not  prevent  them  from  drying, 
however,  as  evaporation  still  continues  although  very  much  slower. 
All  of  these  observations  will  help  the  student  to  gain  an  under- 
standing of  carburetion. 

Volatile  Liquids. — If  a  pan  of  lubricating  oil  be  placed  in  a  room 
the  smell  or  odor  from  it  may  be  detected  only  when  close  to  it,  if  at 
all.  If  a  pan  of  kerosene  is  placed  alongside  of  the  other  pan  the 
fumes  from  the  latter  may  be  detected  more  easily  and  at  a  greater 
distance.  If  a  pan  of  low  grade  gasoline  is  placed  in  the  room  it 
will  be  detected  by  the  odor  of  the  fumes  at  a  still  greater  distance, 


Fuel  Systems 


221 


222  Automotive  Trade  Training 

and  a  pan  of  high  test  gasoline  at  a  still  greater  distance.  In  other 
words,  one  liquid  is  more  easily  and  readily  evaporated  than  another. 
It  is  only  the  natural  vaporization  or  evaporation  which  causes  the 
fumes  to  rise  into  the  air  where  their  presence  is  detected  by  their 
odor.  The  gasoline  is  spoken  of  as  being  more  volatile  than  the 
kerosene.  Alcohol,  benzine,  and  certain  other  liquid  fuels  are  also 
very  volatile  meaning  that  they  easily  float  away  on  the  atmosphere. 

Heat. — If  it  is  desired  to  vaporize  large  quantities  of  water  with- 
in a  short  space  of  time,  heat  is  applied  to  it  until  it  boils  and  steams. 
The  greater  the  heat  applied,  the  faster  it  boils  and  steams  away 
into  the  atmosphere.  The  same  is  true  of  the  volatile  liquids,  or  in 
this  case  of  the  volatile  liquid  fuels.  The  less  volatile,  or  the  heavier 
the  fuel,  the  greater  the  degree  of  heat  required.  Hence,  the  terms 
low  grade  and  high  test  fuels. 

Vacuum. — A  common  laboratory  experiment  is  to  place  a 
quantity  of  water  in  a  glass  flask.  Exhausting  or  drawing  off  the  air 
from  over  the  water,  or  in  other  words,  creating  a  vacuum  in  the 
upper  part  of  the  flask  will  cause  the  water  to  start  boiling  even 
though  the  temperature  of  the  water  is  that  of  the  atmosphere  of 
the  room.  The  boiling  temperature  of  water  is  212  degrees  Fahren- 
heit. This  is  with  normal  atmospheric  pressure  at  sea  level.  Water 
boils  more  quickly  on  the  mountain  top  than  at  sea  level.  This  is 
due  to  decreased  air  pressure  on  the  surface  of  the  water.  Reduction 
of  pressure  hastens  vaporization  or  evaporation.  This  was  evidenced 
when  the  water  in  the  flask  started  boiling  at  a  temperature  less  than 
100°  ;  but  it  requires  that  practically  all  pressure  be  removed  from  it. 

Spraying. — If  a  quantity  of  liquid  is  sprayed  into  the  atmosphere 
from  a  nozzle  it  will  be  broken  up  into  very  fine  particles.  The  finer 
or  smaller  the  nozzle  the  finer  will  be  the  spray.  This  results  in 
atomization,  that  is,  the  small  particles  of  liquid  are  separated  from 
each  other.  The  more  complete  the  atomization  is,  the  more  com- 
plete is  the  process  of  vaporization,  and  the  more  highly  is  the  air 
charged  with  the  liquid. 

Vaporization  and  Carburetion. — The  student  has  had  his  atten- 
tion focused  on  these  matters  with  which  he  is  already  more  or  less 
familiar  in  order  that  he  may  understand  the  manner  in  which  these 
natural  laws  and  principles  are  made  use  of  in  carburetor  design.  By 
utilizing  these  principles  of  vaporization  and  evaporation  gasoline  is 
added  to  air  in  proper  proportion  to  give  an  explosive  fuel,  and 
carburetion  is  completed. 

Air  bearing  heat  is  drawn  up  through  the  carburetor  where,  in  a 
partial  vacuum,  the  volatile  fuel  is  sprayed  into  it.  All  principles 
and  features  of  carburetor  design  harmonize  and  cooperate  to  make 
vaporization  and  carburetion  almost  instantaneous. 

Carburetor  Design. — Carburetors  are  so  designed  and  built  as 


Fuel  Systems 


223 


to  make  use  of  all  the  features,  principles,  and  natural  laws  enumer- 
ated and  explained  above.     Air  is  drawn  in  through  a  stove  where  it 


is  heated.  Next  it  is  drawn  into  a  venturi  tube  arrangement  called 
the  mixing  chamber.  Here,  due  to  its  velocity,  it  creates  a  vacuum 
which  in  turn  draws  or  sucks  gasoline  from  the  spray  nozzle.    As 


224  Automotive  Trade  Training 

this  gasoline  leaves  the  nozzle  it  is  atomized.  Vaporization  is  com- 
pleted by  the  vacuum  and  heat.  When  the  proportions  of  air  and 
gasoline  are  correct  the  carburetion  of  the  fuel  is  completed.  Car- 
buretion  might  be  defined  as  the  act  of  spraying  a  volatile  fuel  into 
the  heated  air  of  a  partial  vacuum  in  such  proportions  that  the  vapori- 
zation effected  gives  a  mixture  which  may  be  compressed  within  the 
engine  and  exploded  with  a  clean  blue  flame. 

Explosive  Mixture. — A  mixture  of  gasoline  and  air  is  explosive 
only  in  certain  proportions.  In  speaking  of  and  considering  the 
proportions  of  air  and  gasoHne  they  are  considered  with  reference 
to  weight  and  not  volume.  One  part  of  gasoline  mixed  with  ten  or 
more  parts  of  air  is  barely  explosive.  It  burns  with  a  reddish  yellow 
flame.  One  part  of  gasoline  mixed  with  twenty  parts  of  air  again 
is  barely  explosive.  This  mixture  burns  with  a  whitish  flame.  One 
part  of  gasoline  mixed  with  fifteen  parts  of  air  might  be  said  to  be 
the  best  proportions.  This  mixture  burns  with  a  clean  blue  flame. 
With  the  very  high  test  gasoline  the  correct  proportion  may  run  as 
high  as  seventeen  to  one  while  with  the  very  low  grade  as  low  as 
thirteen  to  one  is  correct. 

In  order  that  the  student  may  understand  carburetor  adjustment 
care  and  repair,  there  are  given  below  certain  conditions  which  he 
must  be  able  to  recognize.  These  will  be  evident  from  the  action 
of  the  engine  under  varying  conditions,  especially  those  having  to  do 
with  speed,  power,  and  condition  of  exhaust  with  reference  to  its 
sound  and  the  color  of  exhaust  gases. 

Rich  Mixture. — A  rich  mixture  is  indicated  by  a  sluggish  motor 
uneven  in  operation.  It  has  less  than  normal  power.  Exhaust  gases 
may  show  black  smoke.  Response  is  slow  on  opening  the  throttle. 
Over-fed  conditions  are  evident.  The  engine  does  not  choke  quickly, 
but  will  die  a  slow  lingering  death. 

The  condition  may  be  remedied  by  adding  to  the  air  supply 
cv  permitting  more  air  to  enter  by  making  proper  air  valve  adjust- 
ments. It  may  also  be  remedied  by  cutting  down  on  the  gasoline 
allowance.     Either  action  will  result  in  leaning  the  mixture. 

Lean  Mixture. — A  starved  condition  is  evident  here.  If  the 
engine  runs  at  all,  it  will  run  faster  than  the  over-fed  motor.  Again, 
it  has  less  than  ndrmal  power.  Its  surest  indication  is  popping  at 
the  carburetor  due  to  premature  ignition,  commonly  called  pre-igni- 
tion.  With  this  condition  present  black  smoke  never  will  be  noticed 
iit  the  exhaust.  Usually,  when  the  mixture  is  leaned  out  too  much, 
the  engine  will  speed  up  for  a  few  seconds  and  then  come  to  an 
abrupt  stop.  With  a  very  rich  mixture  the  engine  may  continue  to 
chug  along  for  quite  a  time. 

This  condition  is  remedied  by  enriching  the  mixture.  To  do  this, 
close  off  some  of  the  air  supply  by  adjusting  the  air  valve  spring. 


Fuel  Systems  225 

Or,  the  same  result  may  be  arrived  at  by  opening  up  the  gasoline 
needle  until  enough  gasoline  is  added  to  the  air  to  give  the  proper 
proportion  for  the  mixture. 

Correct  Mixture. — When  the  correct  mixture  is  reached  from 
either  of  the  two  extremes  explained  above,  it  will  be  evidenced  by 
a  smooth  running  engine  and  a  return  to  normal  power.  In  the  case 
of  a  return  to  normal  power  from  an  over-rich  mixture  some  little 
time  will  be  needed  to  drive  out  the  logged  gases  and  burn  the  spark 
plugs  clean  of  soot  and  smoke,  which  is  bound  to  be  left  in  the 
cylinder  and  on  plugs  by  an  over-rich  mixture.  The  proper  mixture 
would  be  evidenced  by  a  clear  blue  flame  if  it  could  be  seen.  If  the 
student  is  familiar  with  the  gasoline  stove  or  torch  he  will  recognize 
this  flame  immediately.  As  the  student  has  doubtless  noticed,  an 
imperfect  mixture  in  the  use  of  a  gas  or  gasoline  stove  usually  burns 
yellow  and  smokes.  This  is  the  condition  in  the  rich  mixture  in 
the  engine  where  the  smoke  and  soot  are  deposited  as  carbon. 

Power. — The  motorist  says  he  has  great  power,  has  no  power, 
or  has  just  average  power  and  speed.  As  a  rule  this  means  good, 
bad,  or  average  combustion  of  the  gases  within  the  cylinders,  which 
is  the  real  source  of  all  power  developed  in  the  car.  Other  conditions 
may  be  present  which  cause  mechanical  troubles,  or  poor  ignition,  but 
the  most  frequent  cause  of  loss  of  power  is  poor  carburetion. 

A  properly  mixed  charge  of  fuel  explodes  with  great  heat  and 
tremendous  expanding  force.  This  forces  the  piston  down  into  the 
cylinder  with  decided  force  and  power. 

A  mixture  containing  too  much  fuel  burns  slowly  rather  than 
exploding.  The  gases  form  slowly  and  push  the  piston  down  as  they 
form.     Their  expanding  power  is  vastly  less. 

The  mixture  which  is  too  lean  explodes  quickly.  The  volume 
of  gases  formed  by  the  explosion  is  insufficient  to  fill  the  entire  com- 
bustion chamber  with  high  pressure  gases.  It  might  be  characterized 
by  comparing  it  with  an  attempt  to  drive  a  heavy  nail  with  a  tack 
hammer.     Not  enough  energy  can  be  developed. 

Venturi  Tube. — Practically  every  type  of  carburetor  utilizes  the 
principle  of  the  venturi  tube  to  hasten  vaporization  of  the  gasoline. 
This  tube  comprises  an  important  part  of  the  mixing  chamber.  The 
venturi  may  be  detected  in  any  of  the  carburetor  illustrations  as  that 
part  having  a  contracted  neck  or  portion  with  the  spray  nozzle  ending 
in  the  throat.  The  velocity  of  the  air  passing  through  the  throat 
or  neck  is  increased.  After  it  is  through  and  there  is  more  room,  the 
air  expands  thus  forming  a  partial  vacuum.  The  gasoline  is  sprayed 
into  this  neck.  This  action  might  be  likened  to  a  column  of  soldiers 
marching  through  a  narrow  portion  of  the  roadway.  After  passing 
through  the  narrow  portion  they  maintain  the  same  speed  but  spread 
out  to  occupy  a  greater  space  on  the  road.     In  other  words,  they  are 


226  Automotive  Trade  Training 

farther  separated.  In  the  case  of  the  air,  the  same  quantity  fills  a 
larger  space,  but  the  particles  are  farther  apart,  or  a  partial  vacuum 
has  been  caused. 

Nozzles. — Many  types  of  nozzles  are  used,  some  fixed  and  some 
adjustable.  In  the  case  of  the  fixed  nozzle  the  auxiliary  air  valve  is 
adjustable.  Where  no  auxiliary  air  valve  is  provided  the  nozzle  is 
always  adjustable.  Where  the  nozzle  is  made  adjustable  it  is  done 
by  providing  a  needle  valve  within  it.  By  controlling  the  size  of  the 
opening,  the  amount  of  gasoline  permitted  to  flow  under  any  and  all 
conditions  may  be  regulated. 

Gasoline  Level. — This  is  maintained  at  all  times  just  below  the 
top  of  the  nozzle  in  the  venturi  tube.  Whenever,  for  any  reason, 
the  level  comes  higher,  the  carburetor  is  said  to  flood.  About  y^" 
is  correct.  If  too  low,  that  is  more  than  3/16",  great  difficulty  will 
be  experienced  in  starting  the  engine.  It  is  also  liable  to  give  trouble 
when  operating  at  low  speeds  due  to  the  fact  that  the  suction  within 
the  venturi  is  insufficient  to  lift  the  gasoline  from  such  a  low  point. 

Float  and  Needle  Valve. — A  float,  either  hollow  metal  or  cork, 
is  provided  to  maintain  the  gasoline  at  the  proper  level.  The  opera- 
tion is  automatic.  The  gasoline  enters  the  bowl  from  the  feed  line, 
the  float  rises  on  the  gasoline  until  at  a  predetermined  point  the 
needle  valve  is  forced  down  on  its  seat  thus  shutting  ofif  the  flow  of 
any  more  gasoline  until  some  has  been  used  out,  at  which  time  the  float 
again  falls  permitting  gasoline  to  flow  until  the  proper  level  is  again 
reached.  The  action  of  the  float  and  the  needle  valve  is  continuous 
while  the  motor  is  in  use.  In  time  the  valve  and  valve  seat  will 
become  worn  to  such  an  extent  by  this  continuous  action  that  it  will 
be  found  necessary  to  replace  them  or  reseat  them  in  order  to  prevent 
the  gasoline  leaking  through. 

Float  Troubles. — A  common  fault  of  either  type  of  float  is  log- 
ging. By  this  is  meant  that  gasoline  has  found  its  way  into  the  float 
and  has  made  it  heavy.  In  the  case  of  the  cork  float  the  shellac  is 
penetrated  and  the  porous  part  of  the  float  is  filled.  In  the  case  of 
the  hollow  float  it  develops  a  small  leak  from  which  air  escapes  and 
through  which  gasoline  enters  the  float.  Dirt  may  lodge  under  the 
needle  valve  and  thus  fail  to  control  the  flow  from  the  feed  line,  but 
if  the  float  sinks  to  the  bottom  of  the  carburetor  bowl  and  fails  to 
give  a  lively  response  when  submerged  the  indications  are  those  of  a 
logged  float.  If  the  float  responds  as  it  should  but  gasoline  continues 
to  flow,  the  trouble  is  with  the  needle  valve.  This  dirt  may  often  be 
washed  out  of  the  valve  by  holding  the  float  down,  thus  allowing  the 
gasoline  to  wash  out  the  valve  as  it  rushes  in.  The  carburetor  shoulJ 
be  drained  occasionally  to  remove  any  sediment  which  has  collected 
in  the  bowl.  This  also  removes  the  water  which  has  collected  at  the 
bottom  of  the  bowl. 


Fuel  Systems  227 

Hot  Air  Stove. — Heat  is  added  to  the  air  as  it  passes  on  its  way 
to  the  carburetor.  The  hottest  exposed  part  of  the  engine  is  the 
exhaust  manifold.  On  this  or  on  the  exhaust  pipe  the  designer  fits 
a  sheet  metal  cover  having  air  passages  arranged  in  such  a  manner 
that  the  air  going  to  the  carburetor  is  drawn  in  and  around  the 
exhaust  pipe,  and  after  being  thus  heated  passes  through  the  flexible 
metal  tube  to  the  carburetor.  Stoves  are  cast  integral  with  the  mani- 
fold in  some  cases. 

Hot  Spot  Manifold. — With  the  use  of  lower  and  still  lower 
grades  of  gasoline  it  has  been  found  necessary  to  increase  the  amount 
of  heat  provided  to  the  incoming  charge.  '  This  is  due  to  the  fuel 
being  less  volatile  as  explained  previously.  It  insures  better  com- 
bustion and  economy  of  operation.  The  incoming  charges  pass  along 
a  wall  heated  by  the  outgoing  exhaust  gases.  The  heat  from  the  one 
chamber  is  transferred  through  the  wall  to  the  gases  in  the  other. 
A  variety  of  forms  of  manifolds  are  in  use  but  the  principle  is  the 
same ;  that  is,  heat  is  added  to  insure  vaporization.  The  manifolds 
are  cast  together.  In  some  cases  pins  are  cast  on  either  side  of  the 
separating  wall  so  that  the  exhaust  gases. heat  these  pins  and  the 
incoming  charge  cools  them  and  is  in  turn  heated.  The  plan  is  being 
adopted  rather  generally. 

Hot  Water  Heat. — Carburetors  and  intake  manifolds  are  some- 
times water  jacketed  to  increase  the  amount  of  heat  available  to  the 
incomxing  fuel  charge.  The  greatest  fault  with  this  system  is  the 
slowness.  The  car  will  travel  from  several  miles  upward  before  the 
proper  temperature  is  secured  to  stop  spitting  of  the  carburetor  and 
to  insure  economic  operation.  The  great  fault  of  ail  carbureting 
systems  is  that  the  raw  gasoline  drawn  in,  in  warming  up  the  gaso- 
line, finds  its  way  down  past  the  pistons  into  the  crank  case  there  to 
work  all  manner  of  harm.  The  water  heat  is  clean  and  will  insure 
a  smooth  running  motor  when  the  proper  temperature  is  reached. 
This  is  about  170  degrees.  Another  method  of  utiHzing  the  heat 
from  the  water  to  do  this  work  is  to  cast  the  intake  manifold  integral 
with  the  cylinder  head.  The  water  in  this  case  is  circulated  around 
the  manifold.  This  construction  is  not  apparent  to  the  casual  observer. 
Manifolds  cast  in  heads  which  are  not  cooled  as  thoroughly  as  was 
the  former  practice  are  also  in  use.  Here  the  direct  heat  from  the 
gases  burning  in  the  cylinders  is  used  to  heat  the  incoming  fuel. 

Exhaust  Gas  Jackets. — These  are  used  in  remedying  carbureting 
systems  of  the  older  cars.  A  jacket  is  provided  around  the  intake 
manifold.  The  ingoing  charge  passing  through  the  manifold  absorbs 
the  heat  through  the  intake  manifold  wall  which  is  heated  by  the 
exhaust  gases  flowing  through  the  jacket.  Only  part  of  the  exhaust 
from  the  engine  is  conducted  through  the  jacket.  The  repairman 
can  often  fit  up  a  car  of  an  older  type  with  this  system  to  good 


228  Automotive  Trade  Training 

advantage.  Each  case  has  to  be  handled  individually  but  results  are 
assured.  Some  carburetors  are  provided  with  jackets  through  which 
part  of  the  exhaust  gases  are  shunted  to  heat  the  gasoline  in  the  bowl. 
The  greatest  difficulty  encountered  here  is  to  keep  the  jacket  free  of 
carbon  deposits. 

Choke  Valves. — When  starting  a  cold  engine,  no  heat  being  avail- 
able, the  vacuum  principle  plus  the  atomizing  effect  of  spraying  the 
charge  from  the  nozzle  must  be  depended  on  entirely  for  vaporization. 
To  increase  the  vacuum  the  air  intake  line  has  a  butterfly  valve  placed 
in  it  which  may  be  closed  to  choke  off  the  air  supply,  thus  causing  a 
richer  charge  of  gasoline  to  be  drawn  into  the  mixing  chamber  where 
the  increased  vacuum  helps  vaporization.  From  this  greater  supply 
of  gasoline,  or  richer  charge,  enough  gasoline  will  be  vaporized  to 
get  the  initial  explosion  and  to  start  the  motor  running.  Immediately 
the  engine  has  started  to  run  under  its  own  power,  it  is  necessary  to 
release  the  choke  valve  to  admit  more  air,  or  the  engine  will  be  choked 
by  the  over-supply  of  gasoline.  Too  much  gasoline  in  the  engine 
cylinders  or  the  combustion  chamber  is  spoken  of  as  flooding  the 
engine.  On  stopping  the  engine  many  drivers  partially  or  wholly 
choke  the  engine  to  insure  ready  starting.  This  is  a  good  practice 
for  extremely  cold  weather.  In  warm  weather  a  flooded  motor  may 
be  the  result. 

The  spring  provided  to  hold  the  choke  valve  open  should  be  in- 
spected occasionally  to  insure  its  being  maintained  in  proper  condi- 
tion. It  should  be  held  wide  open  at  all  times,  excepting  only  when 
its  use  is  desired.  If  it  becomes  loose  and  swings  about,  the  engine  is 
certain  to  run  unevenly. 

Air  Valves. — In  order  to  maintain  the  proper  mixture  of  air  and 
gasoline  that  is  15  to  1  by  weight  at  all  speeds,  it  has  been  found 
necessary  to  equip  the  carburetor  with  some  device  which  will  auto- 
matically maintain  these  proportions  after  the  spray  nozzle  has  been 
adjusted  properly.  This  is  handled  differently  by  the  various  car- 
buretor designers.  One  method  long  popular  requires  that  an 
auxiliary  air  valve  be  placed  in  the  carburetor  in  such  manner  that  it 
may  be  acted  on  as  the  inrush  of  air  or  suction  becomes  greater  at 
the  higher  engine  speeds.  This  auxiliary  air  valve  is  shown  in  a 
number  of  the  illustrations  of  carburetor  sections.  Its  position  should 
be  studied  carefully.  It  serves  the  one  purpose  of  maintaining  the 
proportion  of  air  and  gas  no  matter  what  its  design,  location,  or 
method  of  control  may  be. 

Were  it  not  for  this  air  valve  the  fuel  charge  would  become  too 
rich,  thus  causing  the  motor  to  operate  unevenly.  The  most  common 
type  of  air  valve  is  the  one  whose  action  is  controlled  by  a  coil  spring. 
The  tension  on  this  spring  is  adjustable  through  a  thumb  nut  arrange- 
ment which  increases  or  decreases  the  tension  on  the  spring.    This 


Fuel  Systems  229 

adjustable  feature  is  necessary  to  insure  the  action  of  the  valve  at 
just  the  position  required  to  prevent  the  mixture  becoming  too  rich. 
The  springs  used  are  very  sensitive  and  are  especially  wound  for  this 
work.  If,  for  any  reason,  the  spring  becomes  damaged,  it  is  best  to 
replace  it  with  a  new  one.  A  repaired  spring  is  likely  to  give  an 
uneven  jerky  action  to  the  valve  thus  causing  the  motor  to  run  very 
unevenly.  Neither  may  these  springs  be  secured  at  random,  but  the 
spring  furnished  by  the  carburetor  manufacturer  should  be  used. 
The  straight  coil  spring  is  not  used  very  largely  for  this  work. 
Either  two  springs  of  varying  tension  are  used,  or  a  spiral  wound 
spring  is  furnished. 

Adjusting  Air  Valve. — If  there  is  a  low  speed  adjustment,  it 
should  be  set  to  obtain  the  best  idling  speed  for  the  engine  while  the 
air  valve  has  enough  tension  on  it  to  insure  its  remaining  closed. 
When  the  proper  setting  for  the  slow  speed  nozzle  has  been  secured 
the  mechanic  may  proceed  to  adjust  the  air  valve.  First  turn  the 
thumb  nut  until  the  tension  is  greater  than  needed.  Open  the  throttle 
quickly.  The  engine  will  give  forth  the  usual  indications  of  too  rich 
a  mixture,  will  be  found  to  be  sluggish,  and  black  smoke  may  possibly 
be  seen  coming  from  the  exhaust. 

Next  release  the  tension  on  the  spring,  testing  each  little  turn  of 
the  thumb  nut  as  suggested  above.  Continue  the  operation  until  a 
point  is  finally  arrived  at,  at  which  the  carburetor  pops  when  the 
throttle  is  quickly  opened.  Next  increase  the  tension  on  the  spring 
until,  when  the  throttle  is  opened  instantly,  the  engine  picks  up  at 
its  best  speed  without  pause  or  backfire.  With  the  setting  at  this 
point  the  car  should  be  tested  for  speed  and  power.  A  little  varia- 
tion may  be  necessary  as  indicated  by  lack  of  power  or  sluggishness. 

Air  valves  are  not  always  controlled  by  spring  tension.  In  some 
cases  they  are  made  to  operate  by  gravity  in  which  case  they  are  not 
readily  adjustable.  The  suction  of  air  draws  the  valve  from  its  seat 
allowing  the  proper  amount  of  auxiliary  air  to  enter  to  maintain  the 
mixture  in  proper  proportions,  15  to  1,  for  all  speeds.  As  speed  and 
suction  decrease,  the  air  valve  drops  back  on  its  seat  forced  down  by 
its  own  weight.  Since  the  air  valve  cannot  be  adjusted,  all  adjust- 
ments must  be  made  on  the  gasoline  nozzle. 

Adjusting  Gasoline  Nozzle. — This  operation  is  performed  in  much 
the  same  manner  as  the  adjusting  of  air  valves.  The  results  arrived 
at  are  the  same.  A  proper  mixture  is  secured.  The  mixture  should 
be  made  too  rich  by  opening  the  nozzle  to  a  point  where,  when  the 
throttle  is  opened  suddenly,  the  engine  is  sluggish  and  fails  to  respond 
in  a  lively  manner.  Other  signs  of  a  too  rich  mixture  are  present. 
Next  close  the  adjustment  a  trifle  making  the  test  of  opening  the 
throttle.  Continue  this  until  the  best  running  point  is  arrived  at  and 
passed.     When  the  lean  point  is  noticed  by  the  nooning  at  the  car- 


230  Automotive  Trade  Training 

buretor,  the  adjustment  must  quickly  be  enriched  or  the  motor  will 
stop.  Continue  increasing  the  supply  of  gasoline  until  again  the 
motor  operates  at  its  best  speed  without  popping  and  without  pause 
when  the  throttle  is  opened  instantly.  Test  the  car  on  the  road  as 
before  and  adjust  finally  as  need  is  shown.  These  instructions  are 
given  to  acquaint  the  student  with  the  principle  of  carburetor  adjust- 
ment as  applied  to  simple  carburetors.  Under  the  description  of 
special  makes  of  carburetors  will  be  found  directions  for  adjustment 
of  same. 

Throttle. — The  throttle  is  a  butterfly  valve  located  in  the  top  of 
the  mixing  chamber  of  the  carburetor.  Opening  the  throttle  means 
opening  this  valve  until,  at  a  wide  open  position,  the  valve  stands  in 
each  case  in  a  position  to  allow  the  maximum  amount  of  air  to  flow 
past  it.  Closed  throttle  means  that  the  valve  rests  almost  straight 
across  the  top  of  the  mixing  chamber.  A  very  small  opening  is  left 
for  the  passage  of  air  on  a  closed  throttle.  In  a  closed  position  the 
engine  is  said  to  run  at  an  idling  speed  meaning  it  is  carrying  no 
load.  Closing  the  throttle  does  not  stop  the  engine  as  in  the  case  of  a 
steam  engine,  but  permits  it  to  continue  at  the  idling  speed  until  the 
spark  is  turned  off.  In  some  models  of  carburetors  a  gasoline  nozzle 
is  introduced  at  the  point  of  closing  of  the  throttle  to  provide  a  spray 
of  gasoline  for  slow  speeds  and  starting  work.  Special  devices  and 
attachments  are  at  times  used  by  designers  in  conjunction  with  the 
butterfly  valve  to  provide  the  throttling  mechanism. 

Metering  Pin. — This  device  is  used  to  control  the  amount  of 
gasoline  entering  the  mixing  chamber.  It  may  be  used  either  as  the 
principal  adjustment  or  merely  as  an  auxiliary  feature.  It  consists 
of  a  long  metallic  pin  fitted  into  a  nozzle  in  such  a  manner  that  it 
carefully  measures  or  meters  the  amount  of  gasoline  permitted  to  flow 
by  it  at  various  speeds  and  settings.  In  some  cases  it  is  actuated 
with  the  throttle  in  fixed  relation  to  the  opening  and  closing  of  the 
same.  In  other  cases  it  operates  in  conjunction  with  air  valve  dash 
pots.  The  metering  pin  in  its  relation  to  individual  design  is  brought 
out  in  the  illustrations. 

Dash  Pot. — The  dash  pot  is  a  separate  gasoline  chamber,  or 
bowl,  in  which  the  gasoline  level  is  maintained  at  the  same  level  as 
that  of  the  carburetor  bowl.  This  is  done  by  the  float  and  needle 
valve  arrangement  which  controls  the  level  in  the  bowl.  A  passage- 
way connects  the  bowl  and  pot.  When  the  auxiliary  air  valve  is 
drawn  down  the  dasher  within  the  pot  forces  up  a  quantity  of  gasoline 
which  is  sprayed  into  the  auxiliary  air  to  insure  acceleration.  The 
dasher,  which  is  connected  to  the  air  valve,  tends  to  hold  same  steady 
and  prevent  fluttering.  The  student  will  study  the  action  of  the 
metering  pin  in  the  designs  utilizing  it  as  described  and  illustrated  in 
the  succeeding  pages. 


Fuel  Systems 


231 


Plain  Tube  or  Compound  Nozzle  Type. — Here  is  found  perhaps 
the  simplest  carburetor  in  point  of  moving  mechanical  parts.  Natural 
laws  and  principles  are  substituted  for  mechanical  devices.  The 
student  was  shown  how  the  low  speed  mixture  grew  too  rich  when 
the  throttle  was  opened  and  the  suction  increased.  To  compensate  for 
this  an  additional  feature  is  provided  so  arranged  that  the  fifel  charge 
is  always  too  weak  or  lean.  The  two  combine  to  maintain  at  all 
speeds  the  proper  mixture.     The  regulation  of  the  amount  of  gasoline 


<— AmnmKE 


SPEB>ADJUSTHENr 


Carbureror  Assembly 

Fig.   238.    MaxweU   Carburetor   in    Section. 


to  the  amount  of  air  is  held  at  15  to  1  automatically.  Adjustments 
for  high  or  low  speeds  may  or  may  not  be  provided  in  carburetors 
using  this  principle,  which  is  called  the  Baverly  principle  after  its 
discoverer. 

Air-Bled  Jets. — In  the  air-bled  jets  a  small  quantity  of  air  is 
admitted  through  and  with  the  gasoline.  This  tends  to  break  up  the 
gasoline  and  make  atomization  more  complete  as  it  is  sprayed  from 
the  nozzle  into  the  mixing  chamber. 

JOB  84.     MAXWELL  CARBURETOR. 

Several  styles  of  carburetors  have  been  used  on  the  Maxwell  25.  The 
photographic  reproduction  shown  in  Fig.  239  is  the  earlier  type.  The  gasoline 
adjustment  is  shown  as  the  needle  valve.     This  valve  is  controlled   from  the 


232 


Automotive  Trade  Training 


instrument  panel  within  certain  limits.  If  the  carburetor  has  been  dismantled 
.and  is  being  reset,  the  needle  valve  should  first  be  turned  all  the  way  to  its 
seat.  Next  it  should  be  opened  to  about  three-fourths  of  a  turn,  after  which 
the  needle  valve  handle  binder  screw  should  be  locked.  This  should  be  with 
the  dash  control  on  center.  Throwing  this  handle  to  the  one  side,  closes  the 
needle  valve  giving  a  leaner  mixture.  Throwing  it  to  the  other  side  gives  a 
richer  mixture  because  the  valve  is  opened.  The  lean  position  should  be  in 
use  for  driving  on  the  level,  while  the  neutral  or  rich  position  will  have  to  be 
used  for  hard  going.  This  is  the  only  adjustment  on  the  carburetor.  The 
auxiliary  air  valve  is  a  hollow  brass  ball  which  is  raised  from  its  seat  by  the 


Gasoline  Shut  Off  Cock 

Gasoline  Line 

Hot  Air  Stove 


Throttle  Lever 


Drain  Plug 


Gasoline  Tank  Outlet 
and  Settling  Chamber 


Float  Valve  Screw  Cap 
Float  Valve 


Needle  Valve  Handle 
Hot  Air  Stove  Door  - 


Needle  Valve  Handle  Binder  Screvi/ 
Needle  Valve 


Gasoline  Line  Packing 


Gasoline  Line  Packing  Nut 
Air  Choke  Valve  


Float  Cfcamber  or  Carburetor  Bt 

!  ioat  Chamber  Drain  Cock 


Fig.   239.    Maxwell   Carburetor   and    Fittings. 

increased  suction  to  admit  additional  air.     This  ball  may  be  seen  in  the.  center 
of  the  cut. 

MAXWELL  25 — 1919.  A  section  of  the  1919  carburetor  is  shown  in  Fig. 
2r58.  This  is  provided  with  two  adjustments.  Proceed  as  follows  to  adjust  this 
carburetor.  With  the  engine  idle  turn  both  idle  screw  and  high  speed  screw  to 
their  seats.  Set  the  throttle  lever  stop  screw  to  the  approximate  idling 
position.  Next  open  the  high  speed  needle  one  and  one-half  turns.  With 
these  adjustments  made  the  engine  should  be  started  and  run  until  it  is  as  warm 
as  actual  service  conditions  would  make  it.  Next  place  the  spark  control  in  a 
retarded  position  and  open  the  throttle  until  a  driving  speed  of  twenty  to 
twenty-five  miles  is  reached.  Next  turn  the  high  speed  needle  to  the  right  or 
close  it  until  the  engine  tends  to  stop  from  too  lean  a  mixture.  Turn  it  open  or 
to  the  left  until  the  engine  shows  signs  of  too  rich  a  mixture.  The  engine  will 
roll  and  show  signs  of  slowing,  choking,  and  stopping.  Next  turn  the  needle 
to  the  right  again  and  at  a  point  about  midway  between  the  two  extremes  will 


Fuel  Systems 


333 


be  found  the  point  of  greatest  speed  as  well  as  of  best  mixture.  Now  the  idle 
adjustment  screw  should  be  set.  The  throttle  should  be  closed  at  this  time. 
Should  the  engine  fire  unevenly,  turn  the  idle  screw  to  the  left  to  enrich  the 
mixture,  or  to  its  seat  to  make  the  mixture  lean  or  poor.  The  approximate 
position  for  this  screw  is  one-half  turn  out.  The  throttle  as  well  as  the  spark 
should  be  fully  retarded. 

JOB  85.     PACKARD  TWIN  SIX  CARBURETOR. 

Single  Jet.     The  Packard  carburetors  are  of  the  single  jet  or  spray  nozzle 
type.     This  nozzle  is  located  in  the  center  of  a  mixing  chamber  or  venturi.     As 


Fiir.  240.     Packard  Car  Carburetor. 

noted  in  the  illustration.  Fig.  240.  both  the  primary  air  and  auxiliary  air  act  on 
the  one  nozzle.  The  primary  air  comes  through  the  usual  type  of  air  passage 
provided  with  a  choker  which  is  used  only  for  starting  or  cold  weather  work. 
The  action  of  mixing  and  vaporizing  is  the  same  as  previously  explained  for 
this  type  of  carburetor.  Heat  is  secured  from  the  hot  water  jackets  around 
the  cored  intake  and  from  the  exhaust  manifold.  The  single  jet  is  not 
adjustable,  but  all  adjustment  is  secured  from  the  auxiliary  air  valve. 

Auxiliary  Air  Valve.  The  illustration  shows  this  in  a  housing  forward  of 
the  mixing  chamber.  It  is  controlled  by  two  springs,  one  within  the  other. 
At  low  or  idling  speed  this  valve  admits  very  little  air.  The  air  supplied  comes 
through  the  other  passage  and  up  through  the  mixing  chamber,  past  the  nozzle, 
where  it  picks  up  the  gasoline.  To  prevent  too  rich  a  mixture,  the  auxiliary 
air  valve  opens  with  increased  suction  allowing  the  needed  air.  This  insures 
the  correct  mixture  at  all  speeds,  as  the  greater  the  suction  the  greater  the 


234 


Automotive  Trade  Training 


action  of  the  air  valve.  Changing  the  spring  tension  affects  the  quality  of  the 
mixture.  Cams  placed  beneath  these  springs  are  controlled  from  the  dash. 
Pulling  the  air  control  button  out  will  increase  the  tension  on  the  springs  thus 
giving  a  richer  mixture.  The  proper  setting  of  the  button,  for  ordinary- 
running,  is  flush  with  the  dash.  If,  for  any  reason,  these  cams  are  disassembled 
the  greatest  care  should  be  exercised  to  see  that  they  are  reassembled  in  their 
original  position.  In  warm  or  hot  weather  it  is  possible  to  so  flood  the  engine 
by  use  of  the  choker  that  the  mixture  cannot  be  fired.  This  is  a  trouble 
experienced  frequently  by  the  inexperienced. 

Throttle.  This  is  of  the  butterfly  valve  type.  As  in  all  cases  the  valve  is 
provided  with  a  set  screw  which  is  adjustable  for  idling  speeds.  The  throttle 
is  so  adjusted  that  there  is  always  room  for  sufficient  mixture  to  pass  to  keep 
the  engine  running  when  the  control  is  all  the  way  back.  Except  for  this 
provision  the  engine  would  stop  whenever  the  control  or  accelerator  were 
returned  to  either  a  normal  or  ofif  position.  To  increase  the  minimum  speed, 
loosen  the  lock  nut  and  turn  the  screw  forward.  To  decrease  the  minimum  or 
idling  speed,  turn  the  screw  backward  or  out.     This  should  be  done  with  the 


Fig.  241.     Tillotson  Carburetor, 
engine  running  in  order  to  note  the  eflfect  on  the  engine,  and  that  the  mechanic 
may  know  from  the  sound  of  the  motor  when  the  best  idling  speed  is  reached. 
Be  quite  certain  to  lock  the  screw  with  the  check  nut  when  the  adjustment  is 
completed. 

JOB  86.  TILLOTSON  CARBURETORS. 

Instructions  for  Adjusting.  All  models  of  Tillotson  carburetors  are 
equipped  with  the  automatic  air  valve  not  adjustable.  The  gasoline  only  is 
adjustable,  and  that  is  regulated  by  adjusting  the  primary  needle  valve 
adjustment  on  the  primary  fuel  supply  nozzle. 

To  secure  the  correct  adjustment,  first  warm  up  the  motor.  Next,  close 
the  throttle  so  that  the  engine  will  run  reasonably  slow.  Then  turn  the 
adjustrnent  to  the  right  or  up  a  little  at  a  time  until  the  motor  commences  to 
slow  down  as  a  result  of  being  starved  of  fuel,  and  then  turn  the  needle  back 
to  the  left  about  one-eighth  of  a  turn.  This  should  give  the  correct  mixture, 
and  if  all  other  conditions  of  the  motor  are  normal,  the  results  obtained  should 
be  a  maximum  of  power  at  the  best  economy  of  gasoline  used. 


Fuel  Systems 


235 


Automatic  Air  Valve. — The  design  of  the  air  valve  provides  a  small  opening 
through  which  the  air  enters  when  the  motor  is  running  at  slow  speeds.  The 
area  of  this  opening  is  so  designed  as  to  equal  the  requirements  of  the  motor 


236  Automotive  Trade  Training 

at  closed  throttle.  The  area  of  the  opening  is  gradually  increased  by  the 
yielding  of  two  flat  steel  reeds  which  are  opened  by  the  atmosphere  pressing 
against  them  from  the  outside  when  suction  or  a  vacuum  is  produced  on  the 
inside  of  the  carburetor.  The  vacuum  corresponds  to  engine  speeds,  likewise 
the  opening  of  the  reeds. 

The  reed  cage  provides  a  seat  for  the  reeds  which  should  normally  lie 
fiat  on  the  seat  thus  sealing  the  valve.  The  maximum  partial  vacuum  will  only 
open  the  reeds  a  small  portion  of  their  maximum  elasticity  thus  insuring  long 
life  for  the  reeds.  The  amount  of  air  required  by  the  motor  at  any  and  all 
speeds  being  predetermined,  the  correct  mixture  is  obtained  by  the  placing  of 
the  fuel  supplying  nozzles  in  the  path  of  the  air  and  supplying  an  adjustment 
to  regulate  the  amount  of  gasoline  to  be  drawn  through  the  nozzles. 

The  position  of  the  secondary  nozzle  is  such  that  it  supplies  gasoline  at 
the  higher  engine  speeds  only.  Since  the  primary  nozzle  supplies  gasoline  at 
all  speeds  an  adjustment  of  it  covers  both  nozzles,  or  rather  the  mixture  for 
any  engine  speed.  If  the  primary  nozzle  adjustment  is  made  correct,  for  slow 
engine  speeds,  then  the  secondary  nozzle,  being  of  correct  size  and  design,  will 
supply  the  correct  amount  for  the  higher  speeds.  The  student  will  note  that 
the  secondary  nozzle  commences  to  deliver  gasoline  at  partially  open  throttle 
and  leaves  ofif  again  when  the  throttle  has  reached  a  like  point  in  the  closing 
operation. 

Warm  Air. — Warm  air  is  essential  to  the  proper  operation  of  the  Tillotson 
carburetors.  Hot  air  stoves  should  always  be  provided.  A  screen  is  provided 
at  the  gasoline  inlet  connection.  This  will  have  to  be  cleaned  from  time  to 
time  to  insure  the  free  flow  of  gasoline  to  the  float  bowl.  The  cold  air  shutter 
should  be  used  during  periods  of  extreme  heat. 

The  choker  valve  should  be  closed  for  starting  only.  "When  the  motor  is 
warm  the  choker  must  be  wide  open  to  insure  greatest  power  and  economy. 
Attention  to  choker  springs  is  necessary  at  times  to  insure  the  proper  working 
of  the  choker  valve  or  strangler. 

JOB  87.     BUICK  CARBURETOR. 

The  carburetor  is  the  instrument  which  measures  the  fuel  charges  for  the 
motor,  and  mixes  them  with  the  proper  amount  of  air  to  form  a  combustible 
gas.  At  a  high  rate  of  speed  the  velocity  of  the  air  entering  increases  until 
the  air  valve  is  lifted  from  its  seat  and  an  additional  amount  of  gasoline  spray 
is  taken  from  the  high  speed  nozzle.  Since  more  air  is  admitted  the  quality  of  the 
mixture  going  to  the  motor  remains  the  same  as  the  demands  increase  or 
decrease.  The  float  maintains  the  gasoline  level  in  the  usual  way.  The  spray 
nozzle  is  located  in  the  mixing  chamber,  and  is  regulated  by  a  needle  valve 
which  constitutes  the  gasoline  adjustment  of  the  carburetor.  It  is  surrounded 
by  the  venturi  tube  through  which  a  portion  of  the  incoming  air  passes  at  a 
high  velocity,  picking  up  gasoline  from  the  end  of  the  spray  nozzle. 

The  mixing  chamber  also  contains  the  air  valve  and  high  speed  nozzle. 
The  air  valve  is  held  to  its  seat  by  an  adjustable  spring  which  forms  the  air 
adjustment.  At  a  high  engine  speed  the  velocity  of  the  entering  air  increases 
until  the  air  valve  is  lifted  from  its  seat  and  an  additional  amount  of  gasoline 
is  taken  from  the  high  speed  nozzle.  The  air  enters  the  carburetor  through  a 
three-way  valve  controlled  by  the  regulator  on  the  dash.  By  means  of  this 
arrangement  the*  air  may  be  taken  from  the  heater  under  the  exhaust  manifold, 
or  directly  from  the  atmosphere.  By  means  of  the  choke  position  the 
carburetor  is  made  to  draw  excessively  rich  charges  for  starting.  The  throttle 
is  the  usual  butterfly  valve  type. 

Exhaust  Heater.— The  upper  end  of  the  mixing  chamber  and  the  venturi 


Fuel  Systems  237 

tube  which  houses  the  slow  speed  nozzle  are  surrounded  by  jackets  through 
which  some  of  the  exhaust  gases  pass.  This  is  the  arrangement  previously 
mentioned  as  assisting  in  vaporization.  A  damper  valve  controlling  the  amount 
of  exhaust  entering  the  jacket  is  controlled  by  the  throttle  levers,  working  in 
conjunction  with  them.  At  low  throttle  speeds  the  throttle  is  wide  open 
permitting  the  greatest  possible  amount  of  heat  to  enter.  At  high  speeds, 
when  the  air  velocity  and  vacuum  is  great  and  less  heat  is  needed,  the  damper 
is  closed.  This  system  of  exhaust  heat  to  carburetor  is  controlled  by  the 
Season  Adjustment  Valve  or  Carburetor  Exhaust  Heat  Jacket  Shut-Oflf  Valve. 
This  valve  is  located  on  the  exhaust  heat  inlet  tube  at  the  end  next  the  motor. 
In  warm  weather,  or  with  high  test  fuels  this  valve  should  be  closed.  This 
shuts  ofif  all  exhaust  heat  from  the  carburetor,  thus  preventing  loss  of  power 
and  overheated  motor.  In  cooler  weather  this  valve  should  again  be  set  open. 
It  is  best  to  keep  it  open  always  unless  loss  of  power  may  be  attributed  to  it. 
Proper  handling  of  it  makes  for  greater  fuel  economy. 

ADJUSTING  BUICK  MARVEL  CARBURETOR. 

1.  Turn  the  gasoline  adjustment  to  the  right  until  the  needle  valve  is 
closed. 

2.  Set  the  air  adjusting  screw  so  that  the  end  of  the  screw  is  even  with  the 
end  of  the  spring  above  it. 

3.  Open  the  gasoline  adjustment  by  giving,  the  screw  one  full  turn. 

4.  Start  the  motor  as  usual,  allowing  it  to  run  with  the  regulator  on  the 
hot  position  until  the  motor  is  warmed  up. 

5.  With  the  spark  lever  fully  retarded  turn  the  gasoline  adjustment  to  the 
right,  closing  the  needle  valve  until  the  motor  idles  evenly. 

6.  Advance  the  spark  lever  and  turn  the  gasoline  adjustment  to  the  left 
until  the  motor  begins  to  miss  or  skip,  indicating  too  much  air;  then  turn  to 
the  right  again  until  the  motor  again  runs  smoothly. 

To  test  the  adjustment  leave  the  spark  lever  advanced  and  open  the 
throttle  quickly.  The  motor  should  accelerate  instantly.  If  it  skips  or  pops 
back,  open  the  gasoline  adjustment  a  little  by  turning  to  the  left.  Do  not 
touch  the  air  adjustment  again  unless  it  should  appear  absolutely  necessary. 
The  best  possible  adjustment  has  been  secured  when  the  gasoline  adjustment 
has  been  turned  as  far  as  possible  to  the  right  and  the  air  adjustment  as  far  as 
possible  to  the  left,  letting  the  motor  run  smoothly  and  accelerate  quickly  when 
the  throttle  is  suddenly  opened.  Care  should  be  exercised  to  keep  the  exhaust 
heat  tubes  and  carburetor  jacket  clean  to  insure  heat  circulation,  which  enables 
the  motor  to  run  better  and  give  greater  efficiency. 

No  attempt  should  be  made  to  adjust  the  carburetor  until  certain  that  the 
motor  has  good  compression  in  each  cylinder;  that  a  good  hot  spark  occurs  in 
each  cylinder  at  the  proper  time;  and  that  gasoline  is  reaching  the  carburetor 
regularly  from  the  vacuum  tank. 

JOB  88.     KINGSTON  CARBURETORS  MODELS  E  AND  L. 
Model  L.    To  Adjust— 

1.  Retard  spark  fully.  Open  the  throttle  about  five  or  six  notches  on  the 
steering  post. 

2.  Loosen  the  needle  valve  binder  nut  on  the  carburetor  until  the  needle 
valve  turns  easily. 

8.  Turn  the  needle  valve  in  until  it  seats  lightly.  Do  not  force  it  or  the 
size  of  the  nozzle  may  be  changed.  Adjust  it  away  from  the  seat  one  and  one- 
half  turns.  This  will  be  slightly  more  than  necessary,  but  will  assist  in  easy 
starting. 

4.     Start  the  motor  and  adjust  the  throttle  position  by  the  quadrant  or  hand 


238 


Automotive  Trade  Training 


control  until  the  motor  runs  at  a  fair  speed.  Do  not  run  too  fast.  Allow  the 
motor  to  run  long  enough  to  warm  up  to  normal  service  conditions.  The  final 
adjustment  may  now  be  made.  This  carburetor  has  but  the  one  adjustrnent, 
that  of  the  needle  valve.  Close  the  throttle  until  the  motor  runs  at  the  desired 
idling  speed.  This  can  be  controlled  by  adjusting  the  stop  screw  orji  the 
throttle  lever. 


Fig.  243.     Kingston  Fuel  Strainer  and  Carburetor. 

Fuel  enters  strainer  at  point  A,  is  strained  by  the  fine  gauze  wire  B,  and,  cleared 
of  all  sediment  and  impurities,  is  taken  into  the  carburetor  at  point  C.  At  the  base 
of  the  strainer  is  a  pocket  to  catch  water  and  sediment.  By  turning  the  cock  E  the 
water  can  be  instantly  drained  at  the  small  port  D.  The  strainer  can  be  easily  cleaned 
by  removing  the  cap  nut  F.  taking  out  the  strainer  and  its  cage,  cleaning  it  and  putting 
it  back  in  place.  This  strainer,  which  will  do  away  with  many  carburetor  troubles,  can 
be   attached   to   any   Kingston  Model   L   or  Model   L2  carburetor. 

5.  Adjust  the  needle  valve  toward  its  seat  slowly  until  the  motor  begins 
to  lose  speed  indicating  a  weak  or  lean  mixture.  Now  adjust  the  needle  valve 
away  from  its  seat  slowly  until  the  motor  attains  its  best  and  most  positive 
speed.  This  should  complete  the  adjustment.  Close  the  throttle  until  the 
motor  runs  slowly,  then  open  rapidly.  The  motor  should  respond  strongly 
without  popping  or  hesitating.  Should  acceleration  seem  slightly  weak  or 
sluggish  the  needle  should  have  such  slight  further  adjustment  as  to  remedy 


Fuel  Systems 


339 


Fig.  244.     Kingston  Dual  Model. 


this  trouble.     When  final  adjustment  is  secured  lock  the  adjustment  or  binder 

nut. 

Care  o£  Carburetor. — The  bowl  of  the  carburetor  is  provided  with  a  drain 

cock    and    should    be    drained    frequently    to    remove     sediment    and    water. 

Gasoline  leaks  should  receive  prompt  atten- 
tion. Flooding  is  a  sure  sign  that  the  float 
valve  is  held  from  its  seat  by  dirt  or  foreign 
matter  of  some  sort.  To  remedy  this,  re- 
move the  needle  valve  cover  and  by  means 
of  a  small  screw-driver  give  the  needle  valve 
a  few  turns.  The  top  of  the  valve  is  pro- 
vided with  a  slot  for  the  use  of  a  screw- 
driver. The  needle  valve  is  held  in  place 
in  relation  to  the  lever  by  means  of  a  ball 
and  socket  joint.  Care  should  be  exercised 
to  see  that  the  joint  is  not  binding. 

It  is  always  worth  while  to  filter  the 
gasoline  being  used.  Failure  to  do  so  will 
give  the  mechanic  work  in  cleaning  out  the 

carburetor  as  the  dirt  finding  its  way  into  the  carburetor  will  clog  fuel  passages 

and  nozzles,  causing  irregular  operation  of  the  engine.     Trouble  of  this  nature 

is  rather  difficult  to  find  at  times,     A  very  frequent  cause  of  trouble  is  a  clogged 

fuel  line. 

Model  E. 
The  construction  as  well  as  action  of  this  carburetor  is  apparent  from  the 

drawing  shown  in  Fig.  244.     Gasoline  is  admitted  at  24  and  continues  to  flow 

until  valve  22  is  seated  due  to  the  bouy- 

ant  action  of   float  5,     The   attention   of 

the   student  is  particularly  called  to   the 

shape  of  the  spray  nozzle  8  which  forms 

a   cup   around   needle   valve   7    above   its 

seat.     The  gasoline  level  is  1/32"  below 

its  top.     This  excess  of  gasoline  is  avail- 
able   for    starting    and    furnishes    a    very 

rich  charge.     After  the  well  is  emptied  it 

does  not  refill  until  the  engine  is  again 

stopped.     The  regulation  of  the  aitiount 

of   gasoline    is   by   means    of   the    needle 

valve    7    seating    at    the    bottom    of    the 

slight  well.     Both  common  and  auxiliary 

air  is  supplied  from  the  one  source  pass- 
ing by  the  controller  or  choke  throttle  11 

located  in  the  air  intake,  after  which   it 

divides.        Constant     air     passes      down 

through    constant   air   passage    3,    thence 

up    through    the    venturi    tube    at    which 

point    it    becomes     thoroughly     impreg- 
nated by  a  gasoline  spray  from  nozzle  8. 

From     the     nozzle     it     then     continues 

up  where  it  is  reunited  with  the  auxiliary 

air   admitted   by   bronze   balls   2.     These 

balls    comprise    the    auxiliary    air    valves 

and  admit  air  as  required  by  the  varying  motor  speeds. 

These  balls,  after  being  lifted  from  their  seats,  remain  floating  in  the  air 

as  long  as  the  vacuum  or  suction  is  sufficient  to  carry  their  weight.     When  the 


Fig.  245.     Kingston  Model  E. 


240  Automotive  Trade  Training 

suction  decreases  with  the  motor  speed  they  return  to  their  seat  thus  shutting 
off  the  auxihary  air  which  is  not  needed  at  the  lower  engine  speeds.  The 
controller  or  choke  is  so  placed  that  it  is  possible  to  cut  off  nearly  the  entire 
supply  of  air.  This  makes  starting  in  extremely  cold  weather  possible  due  to 
the  high  degree  of  vacuum  produced  at  the  venturi  and  the  rich  mixture  which 
is  consequently  drawn  in. 

Facts  to  Remember. — It  is  essential  that  the  level  of  the  fuel  in  the  bowl 
is  constant  and  of  proper  height;  that  is  from  1/32"  to  1/16"  below  the  top  of 
the  fuel  nozzle  8.  This  may  be  ascertained  by  removing  the  two  caps  No.  1 
and  balls  2  opposite  each  other  to  permit  light  to  enter  one  of  the  holes.  Under 
no  circumstances  use  an  open  flame  for  this  inspection.  The  level  may  be  seen 
through  the  side  opposite  the  one  the  light  is  reflected  in.  Needle  valve  7 
should  be  removed  before  attempting  to  check  up  the  gasoline  level.  Should 
the  level  be  found  too  high,  bend  the  float  lever  4.  If  too  low,  raise  it  in  the 
same  manner.  The  main  reason  for  keeping  the  level  rather  closely  adjusted 
is  to  assist  in  easy  starting. 


Fig.  246.    Reo   Rayfield   Carburetor  and   Heater. 

JOB  89.     RAYFIELD  CARBURETOR  MODEL  L  L  3P. 

The  illustration  of  the  carburetor  and  manifold,  (Fig.  246),  is  the  equipment 
used  on  the  Reo  Car.  The  Rayfield  Carburetor  is  provided  with  two  gasoline 
adjustments,  but  no  air  adjustment.  The  student  or  mechanic  should  bear  in 
mind  that  both  adjustments  are  turned  to  the  right  for  a  richer  mixture  as 
indicated  on  the  adjustment  screw  heads.  As  in  all  cases,  the  mechanic  should 
make  certain  that  there  are  no  obstructions  in  the  gasoline  lines,  that  manifold 
connections  are  absolutely  tight  and  free  from  air  leaks,  that  valves  and  ignition 
are  properly  timed,  and  that  there  is  a  hot  spark  in  each  cylinder.  x\lways 
adjust  the  carburetor  when  the  motor  is  warm  as  in  service  conditions  and  have 
the  steering  column  control  set  at  run  position.  Low  speed  adjustments  must 
be  completed  before  attempting  to  set  high.  Adjustments  made  for  high  speed 
will  not  in  any  way  affect  the  low  speed  adjustments.    A  low  speed  adjustment 


i^UEL  Systems  ^41 

must  not  be  used  to  secure  a  high   speed   mixture.     The   adjustments   of  the 
Rayfield  once  set  can  not  change  as  they  are  positively  locked. 

Adjusting  Low  Speed. — With  the  throttle  closed  and  the  control  on  run 
position,  close  the  nozzle  needle  by  turning  the  low  speed  screw  to  the  left 
until  the  block  U  slightly  leaves  contact  with  the  cam  M.  Then  turn  to  the 
right  for  about  three  complete  turns.  Start  the  motor  (see  starting  instruc- 
tions), and  allow  it  to  run  until  warmed  up  to  a  temperature  of  about  170 
degrees.  After  the  motor  has  become  thoroughly  heated,  push  the  control 
lever  all  the  way  over  on  the  run  position.  Then,  with  retarded  spark,  close 
the  throttle  until  the  motor  runs  slowly  without  stopping.  Now,  with  the 
motor  thoroughly  warm,  make  the  final  low  speed  adjustment  by  turning  the 
low  speed  screw  to  the  left  until  the  motor  slows  down  and  then  turn  to  the 
right  a  notch  at  a  time  until  the  motor  idles  smoothly.  If  the  motor  does  not 
throttle  low  enough  turn  the  stop  arm  screw  A  to  the  left  until  it  runs  at  the 
lowest  number  of  revolutions  desired.  The  quality  of  the  mixture  can  be  tested 
as  follows: 

With  the  shutter  of  the  heater  body  open,  it  is  possible  with  the  finger  to 
press  gently  on  the  air  valve  so  as  just  to  unseat  it  and  admit  more  air  into  the 
carburetor.  If  the  motor  begins  to  pick  up  in  speed  it  indicates  that  the 
mixture  is  too  rich.  Turn  the  adjusting  screw  a  notch  or  two  to  the  left  for 
less  gas.  Open  the  throttle,  allow  the  motor  to  speed  up,  then  close  the 
throttle.  After  tlie  motor  steadies,  repeat  the  operation.  If  the  motor  begins 
to  die  immediately  when  the  air  valve  is  opened  in  the  manner  outlined  above, 
the  mixture  is  too  light.  Turn  the  screw  a  notch  or  two  to  the  right  for  more 
gas.  Wait  a  few  moments  until  the  new  mixture  has  had  time  to  enter  the 
motor  and  repeat  the  operation  again.  When  the  mixture  is  right  the  motor 
will  hold  its  speed  for  several  seconds  after  the  air  valve  is  opened  in  this 
manner  before  it  begins  to  die  gradually. 

Adjusting  High  Speed. — Advance  the  spark  about  one-quarter  way.  Open 
the  throttle  rather  quickly.  Should  the  motor  backfire  it  indicates  a  lean 
mixture.  Correct  this  by  turning  the  high  speed  needle  adjusting  screw  to  the 
right  about  one  notch  at  a  time  until  the  throttle  can  be  opened  quickly  without 
the  motor  backfiring.  If  loading  or  choking  is  experienced  when  running 
under  a  heavy  load  with  the  throttle  wide  open  it  indicates  a  mixture  too  rich. 
This  can  be  overcome  by  turning  the  high  speed  adjustment  to  the  left. 

Starting  Engine  With  Rayfield  Carburetor. — Close  the  throttle  and  hold 
the  carburetor  control  all  the  way  over  on  the  starting  position.  When  the 
motor  starts  firing,  open  the  throttle  slightly  and  return  the  control  to  the 
running  position  as  fast  as  the  operation  of  the  motor  will  permit.  If  returned 
too  quickly  before  the  motor  has  warmed  up  the  lack  of  heat  and  consequent 
poor  vaporization  will  cause  backfiring  and  popping  at  the  carburetor.  When 
the  motor  is  warmed  up  the  lever  must  be  set  and  left  on  the  run  position,  or 
the  rich  mixture  drawn  in  will  cause  trouble  with  the  lubricating  system.  This 
trouble  is  due  to  the  excess  or  unburned  gasoline  finding  its  way  down  past  the 
pistons  into  the  crank  case  and  thinning  out  the  oil.  Where  this  condition  does 
obtain,  the  oil  should  be  drained  each  500  miles  and  replaced  with  fresh  oil. 

Priming  for  Starting. — When  the  lever  is  in  the  starting  position  it  is 
advisable  to  inspect  the  carburetor  from  time  to  time  to  determine  that  the 
steering  column  control  when  set  at  start  pulls  the  eccentric  arm  on  the 
carburetor  back  far  enough  to  depress  the  small  primer  plunger  on  the 
carburetor.  This  plunger,  when  down,  opens  a  bypass  to  the  float  chamber, 
thus  permitting  the  motor  when  starting  to  draw  gasoline  directly  from  the 
bowl.  The  student  will  readily  understand  the  reason  for  keeping  this  closed 
when  the  car  is  in  service,  as  the  vaporization  of  the  low  grade  gasoline  in  use 


242  Automotive  Trade  Training 

is  very  difficult  except  with  the  proper  amount  or  degree  of  vacuum,  heat  and 

atomization  as  explained  earlier  in  the  chapter. 

General  Information  on  the  Rayfield. — The  nozzles  should  never  under  any 
circumstances  be  changed.  The  float  level  rarely  needs  attention.  The 
automatic  air  valve  is  always  closed  at  low  speeds  or  when  the  engine  is  not 
running.  Never  adjust  a  carburetor  unless  the  motor  is  hot.  The  float 
chamber  should  be  drained  occasionally  through  plug  Y  to  remove  water  and 
sediment  which  may  have  accumulated.  Also  occasionally  flush  out  the  dash 
pot  through  the  drain  cock  X. 

To  clean  the  strainer  trap  at  the  bottom  of  the  float  chamber  shut  oflf  the 
gasoline  supply  and  remove  the  nut  S.  Next  remove  and  clean  the  gauze.  In 
replacing  the  trap  be  certain  that  the  gaskets  are  in  place  and  that  the  nut  is 
drawn  up  firmly  to  insure  a  tight  joint.  The  trap  may  be  drained  only  by 
shutting  off  the  gasoline  supply  and  removing  the  plug. 

Hot  Air  Regulation. — As  stated  previously,  the  present  fuel  conditions 
require  the  application  of  heat  to  the  carburetor.  More  heat  is  needed  in  winter 
than  in  summer  if  perfect  vaporization  of  the  fuel  is  hoped  for.  The  upper 
automatic  air  valve  opening  of  the  Rayfield  carburetor  is  connected  to  a  heater 
which  is  provided  with  a  shutter  for  controlling  the  air  temperature.  The 
heater  body  is  marked  in  raised  letters  Winter  and  Summer.  During  warm 
weather  the  shutter  should  be  turned  to  the  Summer  position.  When  so  turned 
the  shutter  cuts  off  the  heater  and  allows  the  air  to  be  drawn  through  the  sides 
of  the  heater  body.  When  the  shutter  is  moved  to  the  Winter  position  it  seals 
the  sides  of  the  heater  body  and  compels  the  air  to  travel  through  a  channel 
formed  in  the  exhaust  manifold.  It  is  obvious  that  the  temperature  of  the  air 
is  greatly  increased  by  passing  through  this  stove  or  heater.  An  opening  is 
also  provided  for  the  constant  air  supply  in  the  hand  hole  cover  which  is 
connected  to  the  carburetor  by  a  tube. 

JOB  90.    ZENITH  MODEL  L  PLAIN  TUBE  COMPOUND  NOZZLE. 

The  Zenith  Model  L  is  designed  on  the  principle  discovered  by  Baverly. 
It  consists  of  a  float  chamber,  a  carburetor  or  mixing  chamber,  a  system  of 
nozzle  and  air  passages,  and  a  hot  air  sleeve  and  regulator.  Gasoline  from  the 
tank  or  feed  line  enters  the  body  through  the  strainer  D,  passes  through  the 
filter  screen  Dl,  enters  the  float  chamber  through  the  needle  valve  seat  S, 
lifting  the  float  F.  As  soon  as  the  gasoline  reaches  a  predetermined  height  in 
the  float  chamber  the  metal  float  F  acting  through  the  levers  B  and  collar  G2 
closes  the  needle  valve  Gl  on  the  seat  S. 

From  the  float  chamber  the  gasoline  flows  through  three  different 
channels  in  various  quantities  and  proportions  according  to  the  size  of  the 
nozzle,  speed  of  motor,  and  degree  of  throttle  opening.  With  the  throttle 
fully  open  most  of  the  gasoline  flows  through  the  channel  E  and  main  jet  G. 
Some  flows  through  compensator  I  which  is  located  at  the  bottom  of  a  well  open 
to  the  atmosphere.  This  well  is  left  open  to  atmospheric  pressure  in  order 
that  the  suction  may  have  no  direct  effect  on  the  amount  of  gasoline  coming 
from  the  compensator  I.  This  amount  is  just  what  will  flow  through  a  hole 
of  fixed  size  and  not  what  might  be  forced  or  drawn  through.  From  this  point 
the  gasoline  flows  through  the  channel  K  to  the  cap  jet  H  which  surrounds  the 
main  jet.  The  main  jet  and  cap  jet  work  together  to  furnish  the  proper 
mixture  whatever  the  speed  of  the  motor  may  be. 

Idling  Device.— At  low  speed  when  the  butterfly  valve  T  is  nearly  closed, 
the  main  jet  and  cap  jet  give  little  or  no  gasoline.     However,  since  there  is 


Fuel  Systems 


243 


Zenith  Carburetor 


Section. 


considerable  suction  on  the  edge  of  the  butterfly  the  gasoline  is  drawn  through 
the  idling  device. 

This  device  consists  of  the  idling  tube  J  withiti  the  secondary  well  P 
inserted  in  the  first  well,  at  the  bottom  of  which  the  compensator  I  is  located 
and  which  is  open  to  the  atmosphere  through  holes  provided  a  small  distance 
below  the  idling  screw  O. 

Gasoline  from  the  compensator  I  flows  through  the  calibrated  hole  in  the 
bottom  of  the  secondary  well  P.  This  is  open  to  the  air  through  the  idling 
screw  O  and  idling  seat  N.  The  idling  tube  J  leads  to  a  hole  located  at  the 
edge  of  the  butterfly  throttle  valve  where  the  suction  is  most  strongly  felt. 
This  suction  lifts  the  gasoline  through  the  idling  tube.  This  amount  of  gaso- 
line combined  with  the  air  passing  the  butterfly  valve  forms  the  idling  mixture. 
Air  Sleeve. — The  air  sleeve  is  provided  with  an  air  strangler  and 
temperature  regulator.  The  two  large  rectangular 
holes  can  be  closed  partially  or  wholly  by  the  brass 
band  held  together  by  a  knurled  headed  screw.  In 
P'ig.  248  the  regulator  is  shown  half  open.  The  air 
•strangler  or  choke  is  operated  by  a  lever  from  the 
instrument  board  and  has  a  coiled  spring  integral 
with  it  to  return  it  to  open  position  when  its  use  is 
not  desired. 


Fig 


Zenith  Air  Sleeve. 


Adjustments. — The  choke  X,  main  jet  G,  com- 
pensator I,  and  secondary  well  P,  need  not  as  a 
rule   be   disturbed.     Their   adjustment   consists   or 


244 


Automotive  Trade  Training 


finding  once  for  all  the  different  sizes  or  settings  for  air  or  gasoline  passages 
suitable  for  the  motor'  in  question.  These  passages  never  vary  and  once 
correct  will  stay  correct.     Where  the  Zenith  is  furnished  as  stat.dard  factory 


Fig.  249.     Zenith   Model   O. 

equipment   the    settings   are    correct.     This    applies   particularly   for   the   high 
speed  adjustments. 

Slow  speed  Adjustment. — The  only  adjustment  vi^hich  may  be  useful  is  the 
slow  speed  adjustment.     The  strength  of  the  suction  in  the  idling  tube  can  be 


low  SPEED  ADJUSTMENT 


Pig.  250.    U.  S.  A.  Standard  Military  Truck  Class  B  Carburetor. 


Fuel  Systems 245 

decreased  by  turning  out  screw  O,  thus  admitting  more  air.  Turning  in  the  screw 
O  increases  the  suction  thereby  causing  the  jet  to  flow  more  gasoline,  making 
the  mixture  richer.  It  should  be  remembered  that  this  effects  the  idling  speed 
only  and  has  no  effect  on  the  high  speed  adjustment. 

Care  of  the  Carburetor. — In  any  car,  especially  the  new  ones,  the  gasoline 
lines  and  tank  may  give  off  scale  rust,  etc.,  which  will  accumulate  in  the  filter 
causing  a  stoppage  of  gasoline  flow  and  consequent  popping  and  missing  of 
the  motor.  Water  will  also  cause  trouble.  In.  this  case  the  carburetor  and 
pipes  as  well  as  the  supply  tanks  must  be  cleaned  thoroughly.  The  carburetor 
must  be  completely  dismantled  to  give  it  a  thorough  cleaning,  but  in  the  case 
of  the  Zenith  there  are  no  adjustments  which  can  be  affected  by  so  doing.  If 
cleaning  is  necessary  be  certain  to  have  the  float  cover  well  seated,  the  needle 
valve  seat  and  various  jets  screwed  down  tight  as  well  as  the  butterfly  throttle 
fastened  properly  on  the  shaft,  so  that  it  may  open  fully.  When  closed,  the 
lower  edge  of  the  butterfly  throttle  should  close  the  idling  hole. 

To  see  if  there  is  gasoline  in  the  carburetor  remove  the  needle  valve  cap 
C  1.  If  the  needle  valve  can  be  depressed  with  the  finger,  there  is  no  gasoline 
in  the  carburetor. 

JOB  91.     U.  S.  A.  STANDARD  CARBURETOR. 

This,  carburetor  shown  in  Fig.  250  is  used  on  some  of  the  Standardized 
Military  Trucks,  Class  B.  It  is  of  the  plain  tube  Compound  Nozzle  type.  The 
Stromberg  Plain  Tube  and  the  Zenith  were  also  used  on  these  trucks.  The 
principle  of  operation  is  similar  to  that  of  the  other  plain  tube  types.  The 
section  shown  illustrates  the  method  of  assembly  as  well  as  the  type  of  nozzles 
and  gasoline  passages. 

JOB  92.     CADILLAC  CARBURETOR. 

This  carburetor  is  a  distinctive  Cadillac  design.  It  is  located  in  the 
channel  between  the  two  cylinder  blocks  and  is  of  the  single  jet  type.  The 
float  bowl  is  directly  under  the  mixing  chamber  and  mi<yht  in  fact  be  said  to 
surround  the  lower  part  of  it.  This  insures  the  prope.  gasoline  level  at  any 
angle  the  car  may  be  in.  In  other  words,  steep  grades  and  high  crowned  roads 
have  no  effect  on  the  heighth  the  gasoline  rises  in  the  spray  nozzle.  Conse- 
quently the  mixture  is  not  affected  by  these  causes  as  is  likely  when  the  float 
bowl  is  to  one  side  of  the  carburetor.  A  ring  shaped  cork  float  encircling  the 
nozzle  is  used.  The  usual  float  valve  mechanism  is  used  to  maintain  the  proper 
gasoline  level. 

Primary  Air. — The  intake  for  this  is  an  oblong  shaped  opening  in  the  side, 
from  which  the  current  of  air  is  deflected  to  the  bottom  of  the  funnel-form 
strangle  tube.  The  venturi  effect  of  the  latter  gives  the  inrushing  air  the  high 
velocity  necessary  to  atomize  the  fuel  and  thoroughly  charge  the  air  with  fuel 
particles. 

Auxiliary  Air. — As  in  all  single  jet  carburetors  the  auxiliary  air  valve  must 
be  depended  on  to  maintain  the  proper  proportions  of  air  and  gasoline  at  high 
speeds.  In  this  case  the  valve  is  a  leather  seated  swing  valve  closed  by  spring 
action.     The  tension  of  this  spring  is  light  and  sensitive. 

Automatic  Leaning  Device. — The  attainment  of  the  desired  mixture  is 
further  assisted  by  means  of  the  automatic  leaning  device.  This  works  as 
follows.  Attached  to  the  right  hand  of  the  throttle  shaft  is  a  shutter  which 
covers  a  slot  in  the   side  of  the  carburetor  body,  whenever   the   carburetor 


246 


Automotive  Trade  Training 


throttle  is  opened  to  a  point  at 
which  the  mixture  threatens  to 
become  too  rich.  When  this 
slot  is  covered  a  passage  is 
formed  from  the  mixing  cham- 
ber to  the  carburetor  bowl  re- 
sulting in  lowering  the  atmos- 
pheric pressure  in  the  latter. 
This  would  cause  a  partial  vac- 
uum in  the  bowl  and  result  in 
less  pressure  being  exerted  on 
the  gasoline  to  feed  or  force  it 
through  the  nozzle  into  the  mix- 
ing chamber.  This  principle 
was  explained  under  the  vacuum 
tank  principle  of  operation.  An 
adjusting  screw  is  provided  for 
regulating  the  opening  of  this 
passage,  and  thereby  the  pro- 
portion of  fuel  in  the  mixture 
when  the  port  is  opened. 

Starting. — To  insure  a  rich 
mixture  in  starting,  provision  is  made  to  increase  the  pressure  or  tension  on  tht^ 
air  valve  spring.  As  usual,  this  is  controlled  by  a  device  on  the  steering 
column. 

Plunger  Pump. — At  the  moment  of  acceleration  a  riclier  mixture  is  needeo. 
This  requirement  is  met  with  a  plunger  pump  operated  in  conjunction  with  ilie 
throttle  lever.  In  action  it  forces  the  needed  fuel  through  the  nozzle. 
Opening  the  throttle  slowly  has  no  effect  on  the  amount  of  fuel  sprayed  from 
the  nozzle  but  when  the  throttle  is  opened  quickly  the  plunger .  exerts  an 
additional  pressure  on  the  gasoline  in  the  bowl  and  causes  more  to  "bev. sprayed 
out  through  the  nozzle  into  the  mixing  chamber.  The  student  will  note  that 
leaning  the  mixture  is  secured  by  decreasing  the  pressure  on  the  gasoline  in 
the  bowl  which  results  in  a  decreased  charge  being  sprayed  out,  and  a  richer 
mixture  is  secured  by  adding  pressure  to  the  surface  of  the  gasoline  in  the 
bowl.  Both  actions  are  such  as  to  leave  the  supply  normal  for  normal  speed 
and  requirements. 

Throttle. — This  is  of  the  usual  type  and  is  controlled  by  either  hand  or 
foot  accelerator.  An  auxiliary  throttle  is  supplied  to  hold  the  throttle  and  air 
valve  steady  when  the  car  is  running  at  slow  speeds  with  wide  open  throttle. 
Heat  is  secured  from  the  water  jacketed  intake  manifolds.  A  gasoline  drain  is 
provided  to  carry  away  the  gasoline  left  from  a  flooded  carburetor. 


Fig.  251.     Sectional  View  of  Cadillac  Carburetor. 


JOB  93.     STROMBERG  TYPE  M.  PLAIN  TUBE  CARBURETORS. 

While. there  are  several  models  of  this  type,  the  action  and  adjustment  of 
all  is  practically  the  same.  The  level  within  the  float  chamber  is  maintained 
as  usual.  From  the  float  chamber  the  gasoline  flows  to  the  well  M,  through 
the  needle  valve  which  is  adjustable.  There  are  two  tubes  in  the  acceler- 
ating well,  one  a  sort  of  standpipe  H,  and  the  other  a  smaller  one  which  is  with- 
in the  first  or  standpipe  and  connects  to  the  idling  jet  K.  The  latter  tube  has 
a  small  opening  in  the  bottom  which  connects  with  the  well.  The  top  end  or 
the  standpipe  H  connects  with  the  cross  passage  N,  which  feeds  the  gasoline 
to  the  eight  small  discharge  holes  in  the  small  venturi  tube  I.  This  Is  located  just 
below  the  main  venturi  tube.    A  rich  mixture  and  not  raw  gasoline  is  fed 


Fuel  Systems 


U7 


through  the  passage  N  because  of  the  small  air  opening  G,  which  enters  the 
well  M  and  supplies  a  certain  amount  of  air  with  the  gasoline  that  is  drawn 
up  the  standpipe  to  the  passage  N.  Holes  in  the  standpipe  below  the  level 
of  the  fuel  feed  gasoline  into  the  standpipe,  while  holes  above  the  fuel  level 
add  air  from  the  top  of  the  well  M,  thus  making  a  very  rich  mixture  to  discharge 
into  the  small  venturi.     At  low  and  idling  speeds  practically  no  fuel  is  drawn 


IDLING  POSITION 


LOW  AND  MEDIUM  SPEED] 


HIGH  SPEED 


WHEN  IDLING  ALL 
THE  GASOLINE  IS 
DRAWN  UP  THE 
TUBL.  J,  THROUGH 
THE  IDLING  JET, 
K,  AND  SPRAYED 
ABOVE  THE  THROTTLE 
VALVE,  T 


AT  HIGH  SPEED 
PRACTICALLY  ALL 
THE  GASOLINE  IS 
DRAWN  THROUGH 
THE  SMALL  VENTURI  , 

TUBE,  I.  MIXED  WITH   AIR    i 
DRAWN  THROUGH  THE 
OPENING,  G.  ABOVE  THE 
WELL,  M. 


AT  INTERMEDIATE  SPEEDS  THE  GASOLINE  IS 
DRAWN  PAST  THE  LOW  SPEED  ADJUSTING 
SCREW,  B,  FROM  THE  TUBE.  J.  AS  THE  THROT- 
TLE IS  OPENED.  MORE  MIXTURE  IS  DRAWN 
THROUGH  THE  SMALL  VENTURI  TUBE,  I,  AND 
AUGMENTS  THAT  DRAWN  FROM  THE  OPEN- 
ING, L. 


Pig,  252.     Stromberg  Allen  Carburetor. 

through  the  small  venturi  due  to  the  fact  that  the  passage  is  closed  by  the 
throttle.  The  gasoline  for  these  speeds  is  taken  through  the  hole  in  the 
bottom  of  the  small  tube  J,  up  to  the  idling  needle  valve  B,  thence  through  the 
passage  K  into  the  intake  manifold  above  the  throttle  valve.  This  gives  a 
rich  mixture  for  idling  and  slow  speed  running.  This  action  is  automatically 
cut  out  as  the  suction  increases  on  an  opened  throttle.  This  occurs  at  about 
eight  miles  per  hour  and  thereafter  has  no  effect  on  the  running  mixture. 

Adjustment. — For   running  position   the   carburetor   is  provided   with   two 
adjustments.    The  screw  F  is  the  main  adjustment  and  controls  the  driving 


248. 


Automotive  Trade  Training 


mixture  for  any  speed.  If  the  screw  F  is  turned  to  the  left,  or  anti-clockwise, 
the  effect  is  to  raise  the  needle  from  its  seat  and  give  a  richer  mixture.  If  the 
needle  is  turned  to  the  right,  or  clockwise,  the  needle  is  brought  closer  to  its 
seat  and  the  mixture  is  made  leaner. 

In  rare  cases  an  entirely  new  adjustment  is  needed.  In  this  case  turn  the 
screw  F  to  the  right  until  it  seats,  then  turn  to  the  left  or  open  three  complete 
turns.  This  should  give  a  mixture  much  too  rich,  and  from  this  position  with 
the  engine  warmed  up  thoroughly  the  final  setting  should  be  effected.  Never 
start  adjusting  a  carburetor  when  the  motor  is  cold  because  of  the  popping  at 
the  carburetor.  Always  wait  until  the  engine  is  thoroughly  warmed  up,  when 
it  may  be  found  unnecessary. 

The  position  for  the  idling  screw  B  is  from  one-half  to  one  and  one-half 
turns  from  the  seat.     Turn  to  the  right  for  less  gas  and  to  the  left  for  more  gas. 

Dismantling  for  Cleaning  and  Repairing. — Refer  to  the  sub-assembly 
photographic  reproduction  for  aid  in  locating  parts  and  their  names. 

1.     To  remove  the  throttle  valve,  unscrew  the  throttle  valve  screws,  then 

remove  the  throttle  from  the  slot  in 
the  throttle  stem.  This  will  also  en- 
able the  workman  to  remove  the 
throttle  stem. 

2.  To  remove  the  air  horn  valve 
and  stem  proceed  in  a  manner  similar 
to  that  for  removing  the  throttle  and 
stem. 

3.  To  remove  the  large  venturi 
tube,  loosen  the  venturi  set  screw  nut, 
and  unscrew  the  set  screw.  If  the 
large  venturi  tube  does  not  now  drop 
out  it  may  be  pulled  out  by  using  a 
wire  hook  applied  to  the  hole  in  the 
large  venturi  tube  just  opposite  the 
idling  needle  valve. 

4.  To  remove  the  small  venturi 
it  is  necessary  to  use  a  socket  wrench 
inserted  from  the  open  top  of  the 
carburetor,  thus  unscrewing  it. 

5.  To  remove  the  accelerating 
well,  first  unscrew  the  idle  tube  with 
of  proper   size.     Next   insert   a   screw 


No.  253.     Stromberg  Carburetor. 


the   holder,   using  an   ordinary   wrench 
driver  and  unscrew  the  accelerating  well. 

6.  To  remove  the  strainer  unscrew  the  strainer  body  stud  which  permits 
lowering  of  the  strainer  body  from  which  the  strainer  may  be  removed  with 
the  fingers. 

7.  To  remove  the  needle  valve  seat,  first  remove  the  float  chamber  covering 
by  unscrewing  and  removing  the  screws  holding  the  same  in  position.  Next  re- 
move the  float.  With  the  proper  size  socket  wrench  unscrew  and  remove  the  float 
valve  seat  nut.  Next  remove  the  strainer  body  stud  and  lower  the  strainer 
body  after  which  the  needle  valve  seat  can  readily  be  unscrewed. 

JOB  94.     THE  STROMBERG  ECONOMIZER. 

Engineers  have  found  that  a  mixture  richer  in  gasoline  is  needed  for  power 
at  wide  open  throttle  than  for  ordinary  passenger  car  driving  at  nearly  closed 
throttle.     The  difference  is  dependent  on  the  volumetric  charge  per  cylinder. 

With  a  carburetor  giving  a  single  mixture  proportion  under  all  conditions. 


Fuel  Systems 


349 


the  best  pulling  power  can  be  obtained  only 
during  ordinary  closed  throt- 
tle driving.  Also,  the  oper- 
ation of  a  motor  on  wide 
open  throttle  is  very  much 
more  sensitive  to  low  tem- 
peratures than  on  a  closed 
throttle.  The  average  driver, 
not  wishing  to  waste  time 
while  the  motor  warms  up, 
sets  the  mixture  unduly  rich 
in  the  winter. 

To  overcome  these  dif- 
ficulties is  the  purpose  of  the 
Stromberg  Economizer  as 
applied  in  Type  L.  This 
economizer  graduates  the 
gasoline  adjustment  posi- 
tively and  definitely  to  the 
point  of  highest  efficiency 
for  each   throttle  position. 

Action     of     Economizer. — The     high     speed     needle 
which    is    supported    b}--    the    lever    arm    at    closed    and 


ith  a  considerable  waste  of  fuel 


Fig,   254.     Stromberg   Economizer. 


is  held  by  a  nut 
open  throttle.  The 
proper  needle  adjustment  for  wide  open  throttle  is  thus  obtained  with  this  nut. 

But,  with  the  throttle  in  ordinary  driving  positions  ranging  from  fifteen 
to  forty  miles  per  hour,  a  roller  drops  into  the  cam  notch  which  permits 
the  lever  arm  to  drop  free  so  that  the  high  speed  nut  is  then  supported  upon 
the  economizer  nut.  This  lowers  the  high  speed  nut  into  its  orifice  and 
partially  cuts  off  the  gasoline  for  these  speeds. 

The  amount  of  drop  can  be  regulated  by  a  pointer  which  thus  gives  a 
special  adjustment  for  greatest  economy  at  these  speeds.  This  is  so  arranged 
that  it  has  no  interfering  effect  on  the  maximum  power  adjustment. 


JOB  95.     DODGE  CARBURETOR. 

Action. — From  the  float  chamber  the  gasoline  flows  through  a  small 
passage  over  to  the  compartment  at  the  base  of  the  metering  pin.  It  fills  this 
compartment  and  rises  part  way  up  the  aspirating  tube.  The  suction  created 
by  the  downward  travel  of  the  pistons  in  the  cylinders  causes  the  air  to  rush 
into  the  mixing  chamber  around  the  aspirating  tube  and  draw  up  the  gasoline. 
Here  the  gasoline  is  vaporized  in  the  manner  previously  explained,  in  the 
former  part  of  this  chapter.  The  air  inlet  is  a  short  tube  to  a  chamber  between 
cylinders  2  and  3,  which  in  turn  is  connected  to  the  hot  air  stove  by  means  of 
another  short  tube.  The  hot  air  stove  is  on  the  exterior  of  the  exhaust 
manifold. 

The  proper  proportion  of  air  and  gasoline  is  controlled  by  means  of  an 
auxiliary  air  valve.  This  air  valve  is  actuated  by  the  suction  of  the  engine. 
The  higher  the  speed,  the  greater  the  suction,  and  the  higher  the  air  valve  is 
lifted  from  its  seat.  The  air  valve  returns  to  its  seat  from  gravity  and  is  not 
controlled  in  any  measure  other  than  suction  to  lift  it  from  its  seat,  and  weight 
or  gravity  to  return  it  to  its  seat.  On  slow  speeds  all  air  needed  is  admitted 
through  holes  drilled  in  the  air  valve,  but  as  stated  previously  the  air  valve 
rises  as  speed  and  suction  increase.  Another  important  function  performed 
by  the  air  valve  in  rising  is  the  lifting  with  it  of  the  aspirating  tube.  This 
action  permits  the  additional  amount  of  gasoline  being  admitted  to  compensate 
for  the  additional  air  and  to  be  mixed  with  it  to  give  a  proper  fuel  charge. 


250 


Automotive  Trade  Training 


Hence,  the  higher  the  aspirating  tube  the  greater  the  supply  of  gasoline 
permitted  to  flow  between  it  and  the  metering  pin  over  which  it  sets.  On  the 
correct  shape  of  this  tapered  metering  pin  depends  to  a  very  large  measure  the 
correct  proportion  of  the  mixture.  If,  for  any  reason,  this  pin  or  the  aspirating 
tube  has  been  damaged  they  should  be  replaced  with  new  ones.  The  aspirating 
tube  in  this  case  is  the  spray  nozzle. 

Adjusting. — If  trouble  is  definitely  traced  to  the  carburetor  the  first  test 


Fig.  255.     Dodge  Stewart  Carburetor. 


is  to  place  a  film  of  oil  around  the  union  of  the  flange  with  the  cylinder  block. 
Observe  whether  this  oil  is  drawn  into  the  engine.  If  gasoline  is  used  to  make 
this  test  the  engine  will  show  a  change  of  speed  if  there  is  a  leak.  If  a  leak  is 
found,  tighten  the  joint.  This  may  require  the  use  of  new  or  shellacked 
gaskets.  If  the  carburetor  does  not  respond  properly  now,  remove  and  disas- 
semble it.  Carefully  clean  the  float  chamber  of  all  dirt  and  sediment.  Clean 
the  valve  mechanism  and  the  dash  pot  of  all  dirt,  sediment  and  corrosion.  See 
that  the  air  valve  works  freely  on  its  guides. 

But  one  adjustment  is  provided  on  the  carburetor.     This  adjustment  varies 
the  relative  heighth  of  the  metering  pin  to  the  opening  of  the  aspirating  tube 


Fuel  Systems  ^51 

or  spray  nozzle.  When  the  dash  control  ratchet  is  in,  the  adjustment  is 
suppdsed  to  be  correct  for  running.  There  is  little  chance  of  this  getting  out 
of  adjustment,  but  if  it  does  the  point  at  which  it  should  be  located  may  be 
found  as  follows. 

The  tapered  metering  pin  is  subject  to  control  within  fixed  limits  by  means 
of  the  dash  control  ratchet  located  on  the  instrument  board.  This  is  for 
starting  purposes  when  a  rich  mixture  is  required.  If  it  has  been  determined 
that  the  fixed  setting  of  the  metering  pin  needs  adjustment  this  may  be  effected 
by  turning  the  stop  screw  to  the  right  or  left  as  desired.  Turning  this  screw 
to  the  right  lowers  the  position  of  the  metering  pin,  allowing  more  gasoline  to 
be  admitted  to  the  spray  nozzle,  thus  enriching  the  mixture.  Turning  the 
screw  to  the  left  raises  the  pin  in  the  nozzle  thus  cutting  off  part  of  the  opening 
and  making  the  mixture  leaner.  The  mechanic  must  keep  in  mind  that  a  very 
small  part  of  a  turn  on  the  screw  is  all  that  is  needed  to  effect  a  change  in  the 
setting.  If  the  carburetor  sputters  or  backfires  at  high  speeds  the  mixture 
requires  more  gasoline.  If  the  engine  loads  and  pulls  unevenly  the  mixture  is 
too  rich. 

Air  Inlet. — As  in  most  cases  the  Dodge  carburetor  secures  part  of  the  hreat 
needed  for  vaporization  from  the  exhaust  through  a  hot  air  stove.  This  tends 
to  prevent  condensation  and  assists  very  materially  in  maintaining  the  correct 
mixture  at  all  times.  The  temperature  of  the  incoming  air  can  be  regulated  by 
means  of  the  adjustable  shutter  on  the  inlet  tube.  In  very  hot  weather  or 
climate  the  tube  may  be  left  off  entirely  without  harm.  At  times  changes  of 
adjustment  of  the  cold  air  shutter  require  corresponding  changes  of  the  stop 
screw  adjustment  as  suggested  in  the  previous  paragraph. 

Draining  and  Cleaning. — First  drain  the  vacuum  tank.  Next  unscrew  the 
filter  cap  and  screen  as  well  as  the  cover  from  the  float  chamber.  The  needle 
valve  should  be  lifted  from  its  seat.  This  allows  the  gasoline  to  flow  out  and 
wash  out  any  sediment,  dirt  and  water  which  may  be  lodged  in  the  float 
chamber  and  permits  cleaning  the  filter  screen  and  other  parts.  Inspect  all 
parts  by  removing  the  float.  Give  particular  attention  to  the  needle  and  needle 
valve  seat  to  see  that  they  are  free  of  dirt,  smooth  and  polished. 

Throttle  and  Controls. — The  controls  are  of  the  type  found  on  the  outside 
of  the  steering  column.  No  particular  attention  is  needed  more  than  to  see 
that  the  gasoline  control  is  so  set  as  to  give  action  on  opening  the  hand  throttle. 
The  car  is  controlled  very  largely  by  the  foot  throttle  or  accelerator.  The 
throttle  is  of  the  usual  butterfly  type.  It  has  nothing  to  do  with  the  propor- 
tions of  the  mixture  but  determines  the  speed  and  power  of  the  motor  merely 
by  the  greater  or  lesser  amount  of  the  mixed  fuel  charge  admitted  to  the 
cylinders. 

JOB  96.     BALL  AND  BALL  CARBURETOR  ON  KING  CARS. 

The  carburetor  is  automatic  and  the  only  adjustment  necessary  is  that  for 
idling  speed.  This  adjustment  is  designed  to  care  for  extreme  climatic  changes 
only.  The  carburetor  shown  in  Fig.  256  is  what  is  known  as  a  double 
carburetor.  Some  of  the  parts  in  the  section  are  shown  out  of  their  natural 
relation  in  order  to  make  the  illustration  clear,  and  to  bring  the  parts  all  into 
one  section. 

Primary  Carburetor. — Referring  to  the  figure,  1  is  the  hot  air  passage  of 
the  primary  carburetor  containing  the  choke  valve  2.  Three  is  the  primary 
venturi  throat  connecting  the  hot  air  passage  with  the  mixing  chamber  6,  and 
containing  the  gasoline  jet  4.  Five  is  another  fixed  air  regulating  orifice 
connecting  the  hot  air  passage  1  with  the  mixing  chamber  6,  and  provided  with 
a  spring  opposed  idling  valve  7  which  is  arranged  to  control  the  air  when  only 


252 


Automotive,  Trade  Training 


small  quantities  are  being  used.     The   throttle  valve  8  is   of  the  usual   type. 
These  parts  constitute  those  operative  in  the  first  stage  of  carburetion. 

Second  Stage. — Referring  to  the  figure  again,  9  is  an  air  passage  leading 
from  the  external  air  to  the  mixing  chamber  6.  This  passage  contains  the 
butterfly  valve  10  which  controls  the  flow  of  air  through  this  passage.  Eleven 
is  a  gasoline  jet  arranged  to  discharge  or  spray  gasoline  into  passage  9  when 
valve  10  is  opened.  Opening  this  valve  permits  the  suction  existing  in  the 
mixing  chamber  6  to  become  effective  on  the  jet  11.  The  student  will  grasp 
immediately  the  effect  the  opening  of  the  valve  has  on  the  jet  11  when  the  car 
is  running.     A   connection  between   the  butterfly  valve   10  and  the   throttle   8 


2-/ 

g-y'/  . 

'         / 

I-'' 

10-^/'' 

3-'  / 

II  -' 

4-' 

Fig.   256.     King   Ball   and   Ball   Carburetor. 

(not  shown)  is  so  arranged  that  when  the  throttle  is  nearly  open  the  furtlier 
opening  of  it  throws  10  wide  open.  At  all  other  times  the  valve  10  is  held 
closed  by  a  spring  (not  shown).  The  student  will  see  that  the  second  stage 
carburetor  is  not  in  use  except  on  hard  pulls  or  beyond  the  average  speeds. 

Pick  Up  Device. — Twelve  is  a  cylindrical  chamber  with  an  extension  13  of 
reduced  diameter  connected  to  the  passage  14  with  the  chamber  15  above  the 
throttle  valve.  The  chamber  12  is  connected  with  the  float  chamber  16  by 
means  of  the  restricted  passage  17  so  that  the  gasoline  in  this  chamber  stands 
on  a  level  with  that  in  the  float  chamber.  Eighteen  is  a  loosely  fitting  plunger 
with  an  extension  19  on  its  upper  end  forming  a  plunger  in  chamber  13.  An 
atmospheric  opening  is  located  in  chamber  12  while  a  passage  21  leads  from 
the  chamber  12  to  the  mixing  chamber  6  through  which  passage  air  is 
constantly  being  drawn  into  the  mixing  chamber. 

In  operation  on  idling  speeds  it  will  be  seen  that  the  vacuum  above  the 
throttle  will  have  the  effect  of  drawing  the  piston  19  up  into  the  passage  13 
and  closing  the  opening  14.  However,  as  the  throttle  is  opened  this  vacuum 
above  the  throttle  is  decreased  and  the  piston  drops,  opening  passage  14. 
Gasoline  will  now  find  its  way  around  18  and  19,  through  14  to  the  incoming 
charge,  and  give  the  extra  amount  of  gasoline  to  insure  a  quick  powerful 
pickup.  This  rich  mixture  is  possible  for  only  a  short  time,  however,  since  the 
hole  17  is  calibrated  and  only  permits  of  a  certain  rate  of  flow  since  the  well 
12  is  open  to  atmospheric  pressure  at  20.  This  is  a  type  of  the  compound 
nozzle  carburetor. 


Fuel  Systems 


.35c'. 


254  Automotive  Trade  Training 

JOB  97.     HUDSON  SUPERSIX  CARBURETOR, 

The  Hudson  carburetor  is  especially  designed  for  the  Super  Six.  It  is 
essentially  a  carburetor  for  high  speed  work  although  it  has  a  wide  range.  The 
throttle  adjustment  must  be  so  set  that  the  engine  will  idle  without  stopping 
as  would  happen  if  the  butterfly  or  throttle  valve  were  permitted  to  close 
entirely.  This  adjustment,  as  in  all  other  types,  is  effected  by  means  of  a  set 
screw.  The  carburetor  is  so  designed  that  it  can  be  depended  on  to  properly 
proportion  the  amount  of  air  to  the  gasoline  at  all  speeds  without  the  attendant 
starving  or  overfeeding.  The  carburetor  is  said  to  be  pneumatically  controlled 
since  no  action  of  the  operator  can  change  the  proportion  of  gasoline  to  the 
air.  The  butterfly  valve  might  be  said  to  be  the  cock  or  faucet  turned  to  admit 
more  or  less  of  the  fuel  mixture.  If  more  power  is  needed  the  throttle  is 
opened  more  widely,  if  less  power  is  needed  the  throttle  is  closed  partially,  or 
wholly.  This  is  regulated  by  the  driver  as  he  actuates  the  accelerator.  The 
width  to  which  the  throttle  valve  is  opened  controls  the  amount  of  air  passing 
to  the  engine.  This  amount  of  air  in  turn  automatically  controls  the  propor- 
tions of  air  and  gasoline  entering  the  mixing  chamber  and  consequently  the 
strength  of  the  fuel  charge  entering  the  cylinder.  In  this  way  it  will  be  seen 
that,  upon  opening  the  throttle  suddenly  at  low  motor  speed,  the  requirement:; 
of  the  motor  are  comparatively  small  and  the  suction  of  the  motor  is  relatively 
weak.  This  suction  controls  the  mixing  of  the  air  and  gasoline  pneumatically 
by  lifting  a  piston  device  which  measures  the  correct  amount  of  mixture 
required  and  permits  it  to  pass  on  its  way  to  the  carburetor.  The  necessary 
velocity  as  well  as  vacuum  at  the  mixing  device  is  controlled  by  the  piston  and 
gives  perfect  vaporization  without  being  compelled  to  use  an  excess  of 
gasoline  to  obtain  this  result.  In  other  words,  the  increase  and  decrease  of 
amount  of  mixture  used  determines  the  size  of  the  mixing  chamber  as  well  as 
the  proportions  of  the  gasoline  drawn  up  to  be  mixed  with  the  air  passing 
through  the  carburetor  at  any  specified  engine  speed.  The  features  incor- 
porated in  this  design  which  are  illustrated  in  Figs.  257  and  258  have  a  very 
decided  effect  in  improving  the  pulling  qualities  of  the  Hudson  motor  especially 
at  low  speeds.  \^ 

Aside  from  the  periodical  cleaning  out  of  the  screen  at  the  base  of  the 
float  chamber  and  draining  off  any  water  and  sediment  which  may  have 
accumulated,  there  are  no  intricate  adjustments  necessary.  The  gasoline 
measured  out  by  the  measuring  or  metering  pin  may  be  controlled  by  the 
gasoline  feed  regulator  connected  to  the  lever  on  the  dash.  In  cold  weather  it 
is  necessary  to  use  a  richer  mixture  than  in  warm  weather  as  is  the  case  with 
all  carbureting  devices.  For  high  altitudes  proportionately  less  gasoline  will 
be  used. 

The  amount  of  gasoline  used  is  dependent  entirely  on  the  ability  of  the 
driver  to  handle  the  dash  lever  controlling  the  proportion  of  gasoline  and  the 
throttle  to  meet  needs  of  travel.  High  speed  and  fast  work  on  hills  requires 
more  gasoline  than  moderate  rates  of  speed.  The  mixture  may  be  set  to  as 
lean  a  point  as  desired  by  the  driver  but  some  loss  of  power  will  be  noted. 
Slower  acceleration  will  be  the  result.  The  cause  of  this  was  explained 
previously.  There  is  just  so  much  power  in  a  drop  of  gasoline.  More  than  the 
limit  may  not  be  taken,  less  than  the  limit  may  be  taken  and  quite  often  is.  A 
rich  mixture  is  poor  economy.  Too  rich  a  mixture  will  surely  give  an  excess 
of  carbon  misfiring  and  undue  wear  and  tear  on  vital  moving  parts.  If  the 
operator  finds  it  necessary  to  enrich  the  mixture  for  starting,  it  should  be  set 
back  as  soon  as  the  motor  has  an  opportunity  to  warm  up.  The  air  control 
lever  should  not  be  in  the  choke  or  hot  positions  after  the  motor  is  warmed 


Fuel  Systems 


255 


to  the  proper  operating  temperature.     This  will  result  in  excessive   gasoline 
consumption  because  the  pneumatic  control  does  not  operate  freely. 

The  only  attention  to  this  type  of  carburetor  will  be  to  see  that  the  filter 
under  the  float  chamber  is  not  clogged,  thereby  restricting  the  flow  of  gasoline. 
The  needle  valve  should  be  watched  that  the   parts   are   seated  properly  to 


llASOLJN 
NWEVEL 


\NEEDLE 

Valve 


PISTON 


MEASURING 
PIN 

GASOLINE' 

FEED 
REGULATOR 


C5ARBURETOR 
Fn-TER  SCREEN 


REMOVE   PLUG  TO 
CLEAN  SCREEN 


DRAIN  COCK 


Fig.  258.    Hudson  Super  Six  Carburetor. 

prevent  flooding.  It  is  necessary  to  note  the  action  of  the  motor  to  determine 
whether  or  not  the  piston  valve  which  is  the  air  valve  is  acting  freely.  An 
excessive  accumulation  of  dust  from  dusty  roadways  will  cause  this  to  stick  at 
times.  If  the  strangler  is  used  for  starting,  the  fact  that  the  valve  is  stuck 
may  not  be  noticed.     The  action  of  the  valve  is  not  absolutely  essential  to 


266 


Automotive  Trade  Training 


driving  the  car,  but  an  experienced  driver  will  recognize  the  trouble  almost 
instantly  due  to  the  fact  that  the  accelleration  and  power  are  below  normal. 
The  valve  may  be  freed  by  removing  the  cover  from  the  valve  cylinder  and 
cleaning  it  with  gasoline.  In  putting  back  the  top  it  is  well  to  add  a  little 
kerosene  to  flush  out  any  remaining  dust  as  the  valve  works. 

JOB  98.     PIERCE  ARROW  CARBURETORS. 

In  Fig.  259  is  shown  the  Pierce  Arrow  Special  Automatic  Carburetor.     The 
same  type,  although  not  the  same  model,  is  used  on  the  Pierce  trucks.     The  one 


Fig.  259.    Pierce  Arrow   Carburetor. 

shown  is  used  on  the  Pierce  Dual  Valve  passenger  car  engine  and  on  earlier 
models. 

Float  Chamber. — The  float  chamber  is  screwed  to  the  carburetor  body  in  a 
fixed  position  and- the  float  is  adjusted  to  maintain  the  gasoline  level  at  a  point 
5/16"  below  the  top  of  the  spray  nozzle  K.  The  opening  in  the  spray  nozzle 
is  regulated  by  valve  H.  When  the  gasoline  falls  below  its  proper  level  the 
float  M  together  with  its  levers  N  drop,  permitting  the  float  valve  to  open  and 
more  gasoline  to  flow.  WHien  the  gasoline  has  again  come  to  the  proper  level, 
the  valve  is  closed.  A  glass  window  P  is  provided  in  the  float  chamber  to  show 
the  heighth  of  the  gasoline.  The  gasoline  feed  is  the  pressure  system.  Dirt, 
water  and  other  foreign  matter  is  held  out  of  the  float  chamber  by  the  trap  Q. 

Throttle,  Needle  and  Reed  Valves. — When  the  engine  is  running  very 
slowly  the  throttle  B  is  just  starting  to  open.  Almost  all  the  air  is  entering 
through  the  passage  R.  Here  it  is  mixed  with  an  amount  of  gasoline  regulated 
by  the  nozzle  S.  The  amount  of  mixture  entering  the  cylinders  at  this  speed 
is  regulated  by  the  screw  E  which  is  really  a  throttle  for  the  small  passage  R. 
The  three  auxiliary  air  inlet  reed  valves  are  closed.  As  the  throttle  B  opens 
more,  the  suction  through  R  becomes  greater  for  a  short  period  and  then  be- 
comes the  same  as  through  the  main  passage.  As  the  motor  speeds  up,  the  light 
intermediate  and  heavy  reeds  open  in  succession,  admitting  more  air. 

Supplementary  Springs  and  Needle  Valve. — The  supplementary  springs  U 


I 


Fuel  Systems  "g'ST 

form  gradual  stops  of  a  progressive  strength  on  the  reed  valves.  The  distance 
between  the  reed  valves  and  the  supplementary  springs  should  be,  for  the  light 
reed  '/i",  for  the  intermediate  and  heavy  valves  5/32".  Once  set,  these  reeds 
require  no  further  attention  in  adjusting  the  carburetor.  There  is  a  supple- 
mentary spray  nozzle  L  provided  with  an  adjustment  needle  valve  J.  This  only 
comes  into  action  at  high  speed  when  the  reed  valves  are  open. 

Adjusting  Carburetor. 

1.  Note  if  the  gasoline  level  is  even  with  the  mark  on  the  post  Or  in  the 
sight-glass  of  the  float  chamber,  the  motor  not  running  and  the  car  on  a  level. 

2.  Disconnect  the  throttle  rod  from  the  lever  and  close  the  main  throttle 
B  tight  by  backing  ofif  on  screw  C.  Adjust  this  screw  until  it  touches  lever  A 
at  the  beginning  of  the  straight  surface,  then  screw  in  one-half  to  three-fourths 
of  a  turn  more  and  tighten  lock  nut  D.  Connect  the  throttle  rod  to  the 
operating  lever  adjusting  the  length  of  the  rod  so  the  throttle  just  begins  to 
open. 

3.  Turn  the  idling  throttle  E  into  the  shoulder  until  the  head  of  the  screw 
seats,  then  turn  back  one  and  one-half  turns. 

4.  Loosen  screw  F  on  lever  G.  Turn  needle  H  to  the  left,  or  until  it  is 
on  its  seat.     Next  turn  to  the  right  to  open  three-fourths  of  a  turn. 

5.  Start  the  motor  by  priming  and  allow  it  to  run  until  it  is  warm.  Open 
the  throttle  until  a  motor  speed  of  twenty  to  thirty  miles  is  obtained.  Adjust 
needle  H.  When  the  motor  runs  best  set  lever  G  at  right  angles  to  center  line 
tightening  screw  F.  Set  the  regulator  on  the  steering  column  in  the  center. 
?'ut  wire  in  lever  G  tightening  screw  I.  This  permits  of  equal  travel  each  way 
from  the  center. 

6.  Loosen  the  lock  screw  on  high  speed  needle  J.  With  the  fingers  screw 
down  until  closed  on  seat.  Next  screw  back  or  open  until  open  from  three- 
eighths  to  five-eighths  of  a  turn. 

7.  Test  the  car  on  the  road.  It  should  not  be  set  to  run  slower  than  five 
or  six  miles.  Always  keep  throttle  screw  E  closed  as  much  as  possible.  If  the 
car  works  best  at  speeds  between  twenty  and  thirty  miles  per  hour  with  the 
regulator  in  the  center  adjustment  on  needle  H  the  carburetor  adjustment  may 
be  considered  correct.  If  at  fifty  miles  there  is  a  need  of  setting  it  to  the  heavy 
position,  the  high  speed  needle  must  be  opened  a  bit  farther.  If  it  runs  best  on 
light  the  high  speed  needle  should  be  closed  a  trifle  as  this  indicates  too  much 
gas  and  too  rich  a  mixture.  When  properly  adjusted  the  entire  range  of  speed 
should  be  available  with  one  setting  of  the  regulator.  It  is,  of  course,  necessary 
to  make  such  adjustments  as  will  care  for  extreme  cold  and  heat.  It  is  for  this 
purpose  that  the  regulator  is  provided.  Great  care  should  be  exercised  to  see 
that  all  locking  or  clamping  screws  and  devices  are  properly  set  after  the 
carburetor  is  set. 

Further  Suggestions. — The  idling  adjustment  does  not  have  any  eflfect  on 
other  adjustments.  It  becomes  ineffective  as  soon  as  the  throttle  has 
uncovered  the  idling  passage.  With  throttle  B  adjusted  and  in  closed  position 
only  a  very  small  amount  of  air  passes  up  and  around  the  nozzle  K.  The 
velocity  of  the  air  is  so  low  that  no  gasoline  is  drawn  from  the  K  or  L  while 
the  suction  or  idling  passage  is  very  high.  The  throttle  screw  E  is  used  to 
control  this  suction  and  velocity. 

Best  results  are  obtained  by  keeping  screw  E  closed  as  far  as  possible.  As 
the  throttle  is  opened  the  idling  passage  E  goes  out  of  action  and  all  gasoline 
comes  from  nozzle  K  in  the  mixing  chamber  or  venturi.  When  the  speed  has 
reached  twenty  to  thirty  miles  per  hour  the  high  speed  valve  or  jet  comes  into 
action   and   begins   to   supply    the   auxiliary   gasoline    to    compensate    for    the 


258 


Automotive  Trade  Training 


auxiliary  air  admitted  through  the  reed  valves  which  are  in  action  as  mentioned 
previously. 

For  starting  in  cold  weather  the  gasoline  regulator  should  be  put  on  heavy 
position.  When  running  on  level  roads  economy  may  be  secured  by  turning 
the  regulator  to  light  position  which  means  a  lighter  or  leaner  fuel  charge. 

The  carburetor  is  heated  in  part  by  means  of  hot  water.  A  cock  is 
provided  to  regulate  the  amount  that  is  flowing.  Except  in  extremely  hot 
weather  this  should  be  wide  open. 

By  opening  the  ventilators  in  the  top  of  the  hood  and  pulling  the  hot  air 
funnel  away  from  the  exhaust  pipe  the  engine  will  run  cooler.  This  is  rarely 
needed  except  in  high  altitudes.  Due  to  the  low  grades  of  gasoline  used  it  is 
best  to  keep  the  engine  well  warmed  up.  Just  below  the  boiling  point  is 
considered  the  most  efficient  temperature.  In  winter  all  heat  is  required  which 
can  be  obtained.  Hot  water  must  be  on  full,  the  cold  air  regulator  at  the 
bottom  of  the  carburetor  closed,  and  the  hot  air  funnel  brought  to  within  one 
inch  of  the  exhaust  pipe.  In  addition  to  this,  at  least  one-half  of  the  radiator 
must  be  covered.  In  colder  climates  it  is  well  to  keep  a  small  portion  covered 
even  in  summertime. 

Care  and  Maintenance. — If  all  gasoline  passages  are  clean  and  free,  and  all 
connections  on  inlet  pipes  are  tight,  the  above  adjustments  will  give  a  quick 
pick-up  and  the  greatest  economy.  Flooding  the  carburetor  is  usually  due  t ) 
dirt  under  the  needle  valve  within  the  float  chamber.  Remove  cap  screw  W 
and  clean  it.  The  screens  X  and  Y  should  be  thoroughly  cleaned  from  time  to 
time.  The  screen  over  the  air  pipe  or  funnel  will  gather  dust  and  dirt.  This 
should  also  have  attention. 


JOB  99.  SCHEBLER  DASH  POT  AIR  VALVE  TYPE  CARBURETOR 

In  adjusting  the  Schebler  of  this  type  first  turn  the  auxiliaiy  air  valve  screw 
A  (Fig.  260)  until  the  air  valve  seats  firmly.     Next  close  the  needle  valve  to 


TXT 
Fig.    260.     Schebler    Carburetor. 


Fuel  Systems 


259 


the  right  until  it  seats.  Do  not  crowd  or  force  a  screw  of  this  nature  onto  its 
seat  as  serious  damage  may  result.  Next  turn  this  screw  open  or  to  the  left 
from  four  to  five  complete  turns.  Next  prime  or  flood  the  carburetor  by  pulling 
up  the  priming  lever  C  and  holding  it  up  for  about  five  seconds.  The  throttle 
should  now  be  set  one-third  open  and  the  motor  started.  The  spark  should  be 
retarded  and  the  throttle  closed  gradually  at  the  same  time  adjusting  screw  B 
until  the  motor  runs  evenly  and  hits  on  all  cylinders. 

When  the  motor  has  a  good  idling  speed  the  intermediate  and  high  speed 
adjustments  should  be  made  on  dial  D  and  E.  Adjust  the  pointer  on  the  first 
dial  D  from  Figure  No.  1  toward  Fig.  3  about  half-way  between.  Advance  the 
spark  and  open  the  throttle  so  that  the  roller  on  the  track  running  below  the 
dials  is  in  line  with  the  first  dial.  If  the  motor  backfires  with  the  throttle  in 
this  position  and  the  spark  advanced,  the  pointer  should  be  moved  a  little  more 
toward  3,  or  if  the  mixture  is  too  rich,  turn  the  pointer  toward  1.  Continue 
the  manipulation  of  these  parts  until  you  are  satisfied  that  the  best  action  is 
obtained  from  the  motor  for  this  or  intermediate  speeds.  The  adjustment  for 
a  wide  open  throttle  is  made  on  dial  E  in  just  the  same  manner  as  that  just 
described  for  intermediate  dial  D. 

Further  Hints. — It  has  been  found  that  the  tendency  is  to  give  the 
carburetor  and  engine  too  rich  a  mixture.  In  adjusting  for  low,  intermediate, 
or  high  speeds,  it  is  best  to  cut  the  supply  'down  until  the  motor  begins  to  back- 
fire and  then  increase  the  supply  a  notch  of  the  needle  at  a  time  until  the  motor 
runs  well  and  hits  evenly  on  all  cylinders.  When  by  this  slow  process  the 
point  is  reached  where  the  engine  is  running  evenly,  do  not  advance  further. 
In  making  adjustments  for  high  speeds  do  not  turn  the  pointers  on  the  dials 
more  than  one-half  of  one  of  the  graduations  before  giving  the  adjustment  a 
test. 

Float  Valve  Levels. — The  top  of  the  cork  float  should  stand  1  1/16"  from 
the  top  of  the  bowl  in  the  one  inch,  and  all  models  up  to  the  two  inch  model. 
The  measurement  is  made,  of  course,  with  the  valve  seated. 

ENGINE  SPEED  GOVERNORS. 

Due  to  the  nature  of  the  truck  motors  in  use  for  heavy  duty  work  it  is  well 
to  take  some  precaution  against  overspeeding  them.     When  a  motor  is  driven 

above  its  rated  speed  for  con- 
tinuous service  and  over  con- 
siderable lengths  of  time  the 
deterioration  due  to  vibration 
and  friction  is  very  high.  It 
is  not  always  the  fault  of  the 
driver  that  the  motor  is  over- 
speeded  as  a  difference  of  a 
few  miles  per  hour  which  is 
barely  perceptible  to  the 
driver  is  the  extra  speed 
which  quite  often  does  the 
damage. 

There  are  a  number  of 
devices  on  the  market  de- 
signed to  control  the  speed 
(R.  P.  M.)  of  the  motor  so 
that  overspeeding  the  motor 
is  a  practical  impossibility. 
The  Pierce  Governor  is  of 
this    type.      Fig.    261    shows 


Fig.  261.    Pierce  Governor, 
how  the  governor  works  and' how  it  is  assembled. 


260  Automotive  Trade  Training 

The  governor  proper  goes  between  the  carburetor  and  the  intake  manifold. 
It  may  be  connected  to  the  driving  agent  by  either  a  solid  or  a  flexible  shaft. 
In  the  governor  valve  box  the  valve  is  normally  in  a  position  which  does  not 
obstruct  the  flow  of  the  gas,  but  it  is  closed  so  as  to  reduce  the  valve  port  area 
immediately  the  motor  has  reached  the  predetermined  speed.  The  valve  is 
actuated  by  what  is  known  as  the  flyball  principle.  The  two  weights  are 
mounted  on  a  spider  which  revolves  on  ball  bearings.  These  two  weights  are 
so  pivoted  that  as  they  increase  in  velocity  they  swing  outward,  thus  forcing  a 
plunger  forward  which  in  turn  operates  the  butterfly  valve.  The  plunger  is 
forced  against  a  spring  calibrated  to  a  standard  pressure  so  that  as  the  velocity 
of  the  weights  decreases  they  return  to  normal  position  and  the  butterfly  opens. 
The  oil  required  for  the  governor  is  supplied  through  the  oil  cup  in  the  case. 
The  revolving  weights  serve  to  splash  this  oil  to  all  moving  parts.  The  action 
is  positive  and  simple  and  requires  little  attention  other  than  proper  adjustment 
and  lubrication. 

INSTALLING  PIERCE  GOVERNOR. 

Begin  the  installation  of  the  governor  by  mounting  the  gears  which  are 
to  drive  the  governor  shaft.  This  may  be  on  the  motor  front  wheel  or  the 
transmission.  To  this  governor  drive  is  then  attached  the  drive  shaft  which 
may  be  either  solid  or  flexible.  *  Flexible  shafts  should  not  be  bent  closer  than 
two  inches  from  either  end,  nor  in  less  than  a  ten  inch  radius.  Do  not  stretch 
the  tubing  or  it  will  develop  oil  leaks.  Should  the  tubing  touch  any  part  of 
the  car  frame  strap  it  solidly  to  prevent  wear  due  to  vibration.  When  solid 
shafts  are  used  be  certain  that  keys  and  key-ways  engage  properly  when 
assembling;  also  that  lock-nuts  are  tightened  after  installation  is  connpleted. 

When  mounting  a  new  governor,  or  replacing  a  carburetor  that  has  been 
removed  for  any  reason,  use  thin  gaskets  of  blotting  paper  between  the  flanges. 
Do  not  use  shellac  as  it  is  very  likely  to  make  trouble  by  causing  the  throttle 
or  butterfly  valve  to  stick.  The  governor  must  always  be  mounted  with  the  oil 
cup  on  top. 

Oiling  Governor. — Before  the  governor  is  put  into  active  service,  the  case 
should  have  four  ounces  of  light  Polarine  or  equal  oil  put  into  it.  Use  an  oil 
not  afifected  by  temperature  changes.  Oil  should  be  replenished  each  thousand 
miles  if  the  governor  is  mounted  horizontal,  oftener  if  mounted  otherwise. 

Solid  shafts  require  no  lubrication,  but  gears  in  angle  or  motor  drives  must 
be  kept  running  in  heavy  oil  or  cup  grease.  Other  parts  of  mechanism  should 
be  oiled  weekly  through  oil  holes  which  are  provided.  For  flexible  shafts  use 
Arctic  No.  3  or  good  heavy  graphite  grease. 

Regulating  Governor  Speed. — Since  the  governor  speed  controls  the  truck 
speed  it  is  sometimes  desirable  to  change  the  speed  adjustment.  First  cut  the 
wire  that  seals  the  adjusting  screw  and  pull  ofif  the  cap  that  holds  it  in  place. 
The  adjusting  screw  is  then  exposed.  Turning  the  screw  to  the  right,  or  clock 
wise,  decreases  the  motor  speed.  Turning  to  the  left  or  anti-clockwise 
increases  the  motor  speed.  When  proper  adjustment  has  been  made  replace 
the  cap  and  seal  same.  This  prevents  anyone  tampering  with  the  adjustment, 
and  prevents  vibration  changing  it. 

JOB  100.     CARBURETOR  JOBS. 

Regrinding  Float  Needle  Valve. — Leaking  or  flooding  is  a  fault  common 
to  all  carburetors.  While  the  fault  may  be  remedied,  it  requires  good  judg- 
ment on  the  part  of  the  operator.  In  the  first  place  the  automatic  mechanism 
is  rather  sensitive  to  dirt.     Any  small  bit  of  dirt  will  hold  the  needle  vahe  open 


Fuel  Systems  261 

and  allow  the  gasoline  to  flow  through  the  valve  until  it  finally  rises  above  the 
spray  nozzle  when  flooding  occurs.  This  may  be  remedied  by  removing  the 
dirt,  if  dirt  is  the  trouble.  If  the  mechanical  fit  is  at  fault  it  may  be  remedied 
as  follows: 

First  remove  the  mechanism  and  see  that  the  valve  aligns  itself  properly 
with  the  seat.  Assured  of  this*  place  a  screw-driver  on  the  upper  end  and  give 
a  grinding  motion  similar  to  valve  grinding.  Do  not  use  grinding  compound 
or  an  abrasive.  A  little  oil  will  be  of  help.  As  the  valve  is  rotated  to  different 
positions  it  is  sometimes  good  policy  to  tap  the  end  of  the  screw-driver  to  help 
the  seating  action.  Needless  to  say,  the  blow  must  be  a  light  tap  with  a  light 
hammer.  A  test  the  mechanic  uses,  to  learn  if  the  valve  is  seating  properly 
without  actually  putting  the  carburetor  into  service,  is  as  follows:  Assemble 
the  valve  and  float  mechanism.  Next  turn  the  carburetor  bowl  upside  down 
or  invert  it  so  that  the  weight  of  the  float  closes  the  valve.  Having  the 
gasoline  connection  in  place,  the  operator  places  his  lips  to  the  fuel  connection 
drawing  air  from  the  fuel  cavity,  thus  creating  a  vacuum  therein.  If  the  job  is 
tight  the  lip  will  be  held  by  this  vacuum,  but  if  a  leak  is  present  air  will  find 
its  way  into  the  fuel  cavity  and  release  the  lip. 


«  ■ 

I 


CHAPTER  10 
FUNDAMENTAL  ELECTRICAL  DATA 

Without  electricity  in  its  applied  form,  the  automobile,  while  not 
an  utter  impossibility,  is  almost  that.  Here  as  elsewhere  is  found 
that  element  of  theory  which  the  student  must  grasp,  in  order  to  have 
the  understanding  of  principles  and  processes  so  necessary  to  intelli- 


Pig.  262.     Packard   Liberty  Aeroplane  Motor  equipped  witli  battery  ignition  units. 

gent  care  and  repair  of  automotive  equipment.  This  is  stated  with 
especial  reference  to  ignition,  starting,  charging  and  lighting  equip- 
ment. 

Since  it  has  been  one  of  the  latter  sciences  to  be  developed,  its 

262 


Fundamental  Electrical  Data 


263 


action  is  not  so  largely  a  matter  of  every-day  thought  and  knowledge, 
as  are  some  of  the  other  sciences.  Also,  there  has  always  been  an 
element  of  mystery  about  it  in  the  minds  of  most  people.  Perhaps 
the  number  of  varied  uses  to  which  electricity  may  be  put  gives  some 
ground  for  this  feeling.     It  will  send  the  wireless  message  half-way 


364 


Automotive  Trade  Training 


around  the  world.  It  will  receive  it.  It  will  send  a  dozen  or  more 
messages  over  one  wire  at  the  same  time.  It  will  receive,  select  and 
differentiate  them  at  the  other  end  of  the  wire.  It  will  light  our 
homes;  heat  them,  too,  if  desired;  cook  our  food,  drive  our  street 
cars,  our  electric  passenger  vehicles,  our  electric  freight  trucks,  or 
our  electric  locomotives  more  powerful  than  the  greatest  steam 
locomotive. 

It  drives  the  innumerable  wheels  of  industry,  guides  the  mariner 
across  the  sea,  or  lifts  a  ton  of  steel  on  the  end  of  a  crane.  No  work 
is  too  big,  too  huge;  no  task  too  fine,  too  delicate,  to  ask  of  this 
public  servant,  provided  only  that  proper  mechanical  equipment  be 
supplied  for  it  to  act  on  or  through  in  doing  the  duty  imposed.  By 
providing  this  proper  equipment,  electricity  is  made  to  light  the 
lamps  on  the  automobile,  start  the  engine  to  turning,  and  fire  or 
ignite  the  fuel  charge  within  the  cylinders. 


- 

Hindi. 

■■-| 

Negative  Ttrmin 

»l 

2 

B^^l 

Conn.clioj  Linli 

«. Poiiliv*  Ttrmintl 

Eledrolylt  Level 
-■ PoJiiivc  Plile 

Nfj.i.ve  Phit 

Rubber  Jar 

1 

'     ^"""--Bridtt 

Fig.  264.     Storage  Battery  with  section  removed. 

Fundamental  Principles. — The  fundamental  principles  of  elec- 
tricity are  always  the  same.  However,  different  mechanical  devices 
are  needed  to  apply  it  to  the  different  purposes  for  which  it  is  used. 
For  instance,  current  drawn  from  the  storage  battery  will  drive  the 
starting  motor,  or  will  light  the  bulbs  within  the  lamps,  or  may  be 
used  to  ignite  the  fuel  charge  within  the  cylinders.  The  same  current 
performs  very  different  types  of  work  with  mechanical  devices 
designed  for  same.  Current  electricity  is  energy,  and  energy  is  what 
is  needed  to  light  the  lamps,  turn  the  starting  motor,  or  jump  the 


Fundamental  Electrical  Data 


^6,5 


spark  plug  points.  The  student  will  learn  in  the  following  pages, hpw 
this  one  form  of  energy  is  engaged  in  doing  the  varied  kinds ,  of 
work.  He  will  learn  as  well  the  laws  and  principles  governing,  its 
workings  as  well  as  methods  of  constructing,  caring  for,  and  replacr 
ing  the  necessary  mechanical  devices.  Many  hours  of  study  as  well 
as  many  days  of  work  will  be  needed  to  fully  understand  the  applica- 
tion of  electricity  through  the  various  devices  to  the  automotive  field. 
In  place  of  the  mystery  surrounding  its  application  will  come  ,a 
delightful  understanding  and  a  keen  appreciation  of  its  powers,  its 
sensitiveness,  how  it  is  produced,  and  its  methods  of  doing  work. 

Source  of  Supply. — Electric  current  may  be  obtained  from  bat- 
teries or  from  magnetic  lines  of  force.  Batteries  may  be  considered 
as  belonging  to  several  classes  as  primary  and  secondary.  Each  of 
these  may  again  be  divided  into  several  classes  or  types.  Magnetism 
may  be  from  the  natural  magnetic  lines  of  force  as  they  flow  from 
the  North  pole  to  the  South  pole  over  the  earth's  surface,  or  from 
natural  lodestones.  In  actual  practice  electric  current  is  taken  from 
the  magneto,  dynamo,  or  generator  armature  wires  as  they  are 
revolved  rapidly  in  a  magnetic  field  produced  either  by  permanent 
magnets  or  electromagnets. 

Primary  Battery. — Primary  batteries  as  used  for  automotive  work 
are  usually  the  commercial  dry  cells.  Wet  cells  are  not  used  in 
conjunction  with  the  automobile.  The  dry  cell  is  no  doubt  familiar 
to  the  student.  It  has  a  pressure  of  one  and  one-half  volts  and  an 
amperage  of  28  to  32  when  new  and  in  good  condition.  To  increase 
the  voltage  a  battery  of  dry  cells  is  set  up,  which  are  connected  in 
series.     Connecting  in  parallel  will  increase  the  amperage  available. 

Secondary  Battery. — Storage  batteries  are 
capable  of  generating  no  current  within  them- 
selves without  first  being  subjected  to  a 
charge  from  an  external  source  which  sets  up 
an  electro-chemical  action  within  the  battery. 
On  being  discharged  a  reaction  takes  place  in 
the  battery.  Since  no  current  is  available 
without  the  initial  charge,  the  battery  is  called 
a  storage  battery.  Each  cell  of  a  storage  bat- 
tery has  a  pressure  of  two  volts,  this  being 
one-half  volt  more  than  the  dry  cell.  The 
amount  of  current  or  amperage  available 
varies  within  a  large  range. 

Magnetic  Lines  of  Force. — To  obtain  cur- 
rent from  magnetic  lines  of  force  a  conductor 
must  be  made  to  cut  them,  and  must  be  ar- 
ranged in  such  a  manner  that  as  it  is  cutting 
the  lines  of  force,  the  electric  current  may  be    tween^  points 


Fig.  265.  Magneto  mag- 
nets with  pole  shoes  at- 
tached. Note  how  the 
magnetic  lines  of  force 
support  the  iron  filings. 
The  center  of  the  field  has 
few  lines  flowing.  The 
flux      always      seeks      the 


266 


Automotive  Trade  Training 


taken  from  the  ends  of  the  conductor.  The  device  used  for  this  is 
known  as  an  armature  and  is  used  in  the  generator  or  magneto.  A 
commutator  or  slip  rings  are  used  to  take  off  the  current.  This  is  de- 
veloped in  the  latter  paragraphs  and  chapters,  k  is  v^ell  to  remember 
at  this  time,  hovv^ever,  that  the  number  of  lines  of  force  cut  and  the 
rapidity  v^ith  which  they  are  cut  determines  in  a  large  measure  the 
pressure  or  voltage,  while  the  amperage  or  amount  of  current  devel- 
oped is  dependent  on  the  size  of  wire  used  to  wind  the  armature,  the 
amount  of  resistance  offered  the  flow  of  current,  and  certain  other 
features  of  design.  The  student,  if  not  already  fitted  with  an  under- 
standing of  electrical  terms,  is  beginning  to  feel  a  need  of  explanation 
with  reference  to  the  simplest  of  them.  He  will  also  wish  to  know 
and  be  able  to  recognize  as  well  as  use  the  symbols  for  these  terms. 


Fig.   266.    Drum   Armature  for  Motor  Generator. 

Volts,  Written  E. — The  pressure,  power,  or  force  which  causes 
an  electric  current  to  flow  along  or  pass  through  electrical  conductors 
is  known  as  a  volt  or  volts.  A  piece  of  water  pipe  may  contain  Water 
but  it  will  not  flow  until  pressure  is  put  back  of  it.  The  pounds 
pressure  on  water  and  the  volts  pressure  on  an  electric  conductor  are 
very  similar  as  far  as  their  use  is  concerned.  They  are  the  force 
causing  the  element  to  flow.  In  the  one  case  volts  cause  a  certain 
number  of  amperes  to  flow  along  the  conductor ;  on  the  other  hand 
pounds  cause  a  certain  amount  of  water  to  flow  through  the  pipe. 
This  is  called  the  water  analogy,  meaning  explanation  of  electrical 
action. 

Ampere,  Written  I. — The  amount  of  current  carried  or  forced 
through  the  conductor  by  the  voltage  or  pressure  is  figured  in  amperes 
and  is  so  stated.  More  amperes  can  be  carried  by  a  large  conductor 
than  by  a  small  one,  although  the  voltage  may  be  the  same  in  each 
case.  The  large  storage  battery  has  a  greater  output  than  the  smaller 
one  just  as  a  barrel  will  hold  more  water  than  a  keg. 

Ohm,  Written  R. — The  ohm  is  the  unit  of  resistance  to  the  pas- 
sage of  electrical  current.  Even  in  such  conductors  as  copper  there 
is  a  certain  amount  of  resistance  to  the  flow  of  electrical  current. 
For  instance,  it  is  easy  to  drive  a  nail  through  a  soft  pine  board.  A 
greater  resistance  is  encountered  in  hardwoods  such  as  oak  or  maple^ 


Fundamental  Electrical  Data  267 

but  if  a  piece  of  iron  or  steel  is  struck  by  the  nail  it  is  impossible  to 
drive  the  nail  into  it. 

Electric  current  passes  over  or  through  most  conductors  very 
readily,  but  if  a  non-conductor  is  in  its  path  it  refuses  to  pass  unless 


-1-^        Positive  fernMnal  of  bai+e-rif  or  ^encrofor; 

—  rfeoofive  terminal  of  boftcri^  or  generator. 

—  _"        Batt€r4  -  Sforo^o  or  drij  cell. 


0 


flrm of ure  ond  brushes    of  motor  ond^onerorM 


-^JTO^     riethod  ojshocwino  an  inductive  coi> 

nethod  of  9hou)in<^  o  non-inductive  coil.  (/l/$o  usad 
to  5houj  inductive  coil  cuhen  thero  i$  no  donK^er 
of  co«/u5ion) 

-H  n  jT    Usedfor   resiston^e  onlu. 

HH^-*    C  ontoc-t  pointa. 

'  ^Tovnd  connections  iro frame  o/cqv^ 


^     Sujffch 


r)         Motor  Brush  Su»ifch 

\/\r  Print a-rij     1 
-fyyyyy*-  SeeondarJ 


C  onde  nser 


— >TV— '      Crossed    ujires  (  Not  connected; 

#  Connected  uuires(fllso  os«d  for  terminafa.) 


Fig.    267.    Method    of   illustrating    conventional    electrical   characters, 

the  pressure  or  voltage  is  very  high.  In  the  case  of  the  nail,  if  the 
driving  force  is  great  enough,  it  may  be  forced  through  a  thin  piece 
of  sheet  metal,  but  it  is  folly  to  try  to  drive  it  into  a  casting  or  the 
anvil.     In  the  case  of  the  electric  current,  if  the  voltage,  pressure, 


268  Automotive  Trade  Training 

or  force  is  great  enough,  it  may  be  made,  to  penetrate  or  pass  through 
a  non-conductor.  This  point  will  want  to  be  held  in  mind  by  the 
student  as  it  has  a  particular  bearing  in  relation  to  the  subject  of 
ignition.  It  also  has  a  more  general  application -to  insulating  or  non- 
conducting materials.  Ohm,  for  whom  the  law  of  electrical  resist- 
ance is  named,  found  that  certain  rules  govern  the  relation  of  the 
amount  of  current  resistance  and  pressure,  or  in  other  and  electrical 
terms,  in  the  relation  of  volts,  amperes  and  ohms.  For  instance,  he 
learned  that  the  number  of  ohms  resistance  was  equal  to  the  pressure 
or  voltage  of  current  divided  by  the  amperes  or  amount  of  current. 
An  example  of  this  is  given.  A  pressure  of  12  volts  will  carry  2 
amperes  through  the  head  light  bulbs.  The  ohms  resistance  is  12 
divided  by  2  equals  6;  or,  knowing  the  ohms  resistance  and  the 
amperage,  we  can  find  the  voltage  by  'multiplying  ohms  times  amperes 
as  6  times  2  equals  12;  or,  knowing  the  voltage  and. the  ohms  resist- 
ance, the  amperes  flowing  may  be  found  by  dividing  volts  by  ohms  as 
12  divided  by  6  equals  2  amperes.  Accordingly,  in  the  shortest  terms 
the  law  is:  Volts  divided  by  amperes  equals  ohms  or  E-hI=R  or 
12-^2=6,  or  ohms  multiplied  by  amperes  equals  volts  or  RXl=E 
or  6X2=12,  or  volts  divided  by  ohms  equals  amperes  or  E-^-R=I  or 
12^6=2. 

Abbreviations  or  Symbols. — E  as  used  to  designate  volts  comes 
from  the  term  Electro-Motive  Force.  The  abbreviation  or  symbol  I 
comes  from  *the  International  Electrical  Congress  of  1893,  and  the 
name  in  full  is  International  Ampere,  written  I.  The  Ohm  is  the  unit 
of  resistance  so  the  symbol  R  is  easily  arrived  at. 

Rating  Electrical  Power. — The  units  of  energy  necessary  to  do  a 
piece  of  work  are  computed  by  multiplying  the  voltage  by  the 
amperage.  Referring  to  the  former  problem  of  lighting  the  bulb,  we 
find  that  12  volts  times  2  amperes  gives  24  units  of  electrical  energy 
needed  to  perform  the  work.  The  discovery  of  this  law  is  attributed 
to  Watt  and  these  units  of  energy  are  called  watts,  so  this  might  be 
written,  volts  X  amperes  =  watts,  or  EXl=W,  or  12X2=24.  Since 
the  watt  is  such  a  small  unit  its  use  is  cumbersome  and  the  kilowatt, 
written  kw.,  meaning  1,000  watts  is  used  in  its  stead.  Since  all  power 
ratings  are  by  horse  power,  the  student  would  do  well  to  learn  that 
746  watts  are  rated  equal  to  one  horse-power  (1  H.  P.),  since  746 
watts  will  suffice  to  raise  330,000  pounds  one  foot  in  one  minute. 

Conductors.— Conductors  of  electrical  current  are  present  on  all 
hands.  All  metals  are  conductors.  Water  and  some  other  liquids  as 
electrolyte  are  conductors.  The  earth  itself  is  a  good  electrical  con- 
ductor. The  human  body  is  a  fairly  good  conductor  as  is  evidenced 
by  the  ease  with  which  a  shock  may  be  obtained  when  touching  a 
heavily  charged  body.  Copper  is  used  almost  universally  as  the 
cheapest  good  conductor.     Iron  wire  is  much  inferior  to  cooper  wire 


Fundamental  Electrical  Data 


269 


?.s  a  conductor.     Larger  sizes  must  be  used  to  carry  a  like  amount 
of  current. 

Non-Conductors  or  Insulators. — Air,  stone,  mica,  porcelain,  glass, 
paraffine,  sealing  wax,  rubber,  vulcanite,  and  certain  other  substances 
as  silk,  cotton,  shellac  and  insulating  enamel  are  good  non-conductors, 
or  as  generally  termed,  insulators.  By  this  is  meant  that  they  prevetit 
the  passage  of  electric  current  from  one  conductor  to  another. 

Positive  and  Negative. — Batteries  are  furnished  with  two  ter- 
minals or  posts  to  which  conductors  may  be  attached  to  obtain  the 
electric  current  therefrom.  One  of  these  is  always  termed  a  positive 
terminal,  marked  +  (Plus),  and  the  other  a  negative  terminal,  marked 
—  (Minus).     Current  flows  out  from  the  positive  and  through  the 


FijT-  26S.  Around  every  wire  carrying  an  electrical  current  there  is  a  magnetic 
whirl.  This  is  always  around  the  wire  and  at  right  angles  to  its  axis-  The  wire  run- 
ning in  many  directions  shows  this.  A  12  volt  current  caused  the  iron  filings  to  be 
arranged   as  shown  on  the  glass.     Wire  is   under  the  glass. 

conductors  and  instruments  returning  to  the  battery  through  the 
negative  terminal.  Some  instruments  are  marked  similarly,  or  they 
may  be  marked  with  the  abbreviations  Pos.  and  Neg.  The  carbon 
on  the  dry  cell  is  the  positive,  while  the  zinc  can,  or  shell,  is  the 
negative.  Methods  of  determining  the  terminals  will  be  noted  from 
time  to  time. 

Magnetism. — Magnetism  should  not  be  confused  with  electrical 
current.  Magnetism  is  a  property  possessed  by  certain  materials 
which  causes  that  material  to  attract  to  it  other  materials.  In  certain 
cases  the  action  is  one  of  repelling  rather  than  attracting.  The  earth 
iself  is  a  huge  magnet.  Lines  of  force  emanate  at  all  angles  from 
the  magnetic  north  pole,  passing  north  over  the  earth's  surface  at 
all  points  to  the  south  magnetic  pole  where  they  re-enter  the  earth. 


270  Automotive  Trade  Training 

These  lines  of  force  are  flowing  at  all  points  at  all  times  and  are 
readily  detected  by  the  magnetic  needle. 

Not  all  materials  may  be  magnetized.  Natural  lodestones  are 
found  in  certain  localities  and  these  exhibit  the  same  characteristics 
as  the  bar  or  horse  shoe  magnets.  Steel  may  be  magnetized  as  may 
also  iron.  Brass,  copper  and  aluminum  are  some  of  the  non-magnetic 
metals. 

Producing  Magnetism.  —  Magnetism  may  be  produced  within 
steel  or  iron,  or  these  metals  may  be  said  to  become  magnetized. 
Iron  may  be  magnetized  by  the  process  of  winding  several  coils  of 
wire  about  it  and  sending  a  current  of  electricity  from  a  battery 
through  it.  The  magnet  so  produced  will  be  found  to  attract  bits 
of  steel  as  nails,  screws,  iron  filings,  etc.  Trying  it  with  a  box  of 
nails  it  is  found  that  a  certain  number  of  nails  cling  to  the  magnet 
directly  while  other  nails  cling  to  those  attaching  themselves  to  the 
magnet.  Quite  a  group  may  be  picked  up  in  this  manner.  Breaking 
the  electrical  connection  from  the  battery  to  the  wire  coil  about  the 
bar  of  steel  will  cause  the  nails  to  drop  away,  and  a  test  will  show 
that  practically  all  of  the  magnetic  strength  of  the  bar  is  gone.  In 
other  words,  since  it  no  longer  possesses  magnetism  it  is  not  a 
magnet.  If  any,  even  a  very  little  magnetism  is  left,  it  is  because 
the  bar  is  not  pure  soft  iron  but  has  some  degree  of  hardness. 

Residual  Magnetism. — This  is  the  amount  of  magnetism  remain- 
ing in  an  iron  core  after  the  current  is  broken  off.  The  softer  the 
iron  and  more  nearly  free  of  foreign  substances  or  alloys,  the  less 
residual  magnetism  is  left  after  the  core  has  been  magnetized 
and  the  current  broken.  This  type  of  magnet  is  called  an  electro- 
magnet because  the  magnetism  is  present  only  when  the  current  is 
flowing.  A  good  electro-magnet  loses  its  magnetism  immediately 
the  current  is  broken. 

Electro  Magnets. — Electro-magnets  may  be  in  many  forms  such 
as  the  straight  bar  or  the  U  bar,  or  the  many  forms  of  pole  shoes  used 
in  electrical  machines.  In  every  case  the  electro-magnet  is  made  by 
winding  coils  of  wire  around  a  piece  of  iron  or  steel  which  is  the 
core  of  the  magnet.  The  number  of  lines  of  force  emanating  from 
the  magnet  is  directly  dependent  on  the  number  of  turns  of  wire  and 
amperage  passed  through  the  coil.  Much  of  the  work  done  by  elec- 
tricity is  dependent  on  the  magnetic  properties  of  steel  and  the  laws 
of  magnetism. 

Magnetic  Poles. — While  with  electrical  current  we  have  positive 
and  negative  terminals,  with  magnetism  we  have  north  and  south 
poles.  The  magnetic  North  Pole  is  said  to  be  some  distance  to  one 
side  of  the  geographical  South  Pole.  Likewise  with  reference  to  the 
South  Pole.  In  the  case  of  magnetic  poles,  in  iron  or  steel,  like  poles 
repel  and  unlike  attract.     If  two  magnets  of  like  strength  are  brought 


Fundamental  Electrical  Data 


271 


together  they  will  repel  each  other,  as  two  north  poles  or  two  south 
poles.  If  two  magnetic  poles,  one  a  south  pole  and  one  a  north  pole, 
are  brought  close  together  they  will  swing  together  and  cling  tightly 


Fig.  269.     Lines  of  force  about  ends  of 
single   magneto   magnet. 


Fig.   270.     Double   Magneto    Magnets, 
like  poles  together. 


Fig.   271.     Single   Magneto    Magnet. 


Fig. 


272.     Double  Magneto   Magnets, 
unlike  poles  together. 


to  each  other  unless  some  means  is  used  to  reverse  the  polarity  of 
one  or  the  other  when  the  two  will  repel  each  other. 

Magnetic  Needle. — The  magnetic  needle  works  on  the  above  prin- 
ciple.   The  needle  itself  is  a  magnetized  steel  bar,  large  or  small.    The 


272 


Automotive  Trade  Training 


lines  of  force  travelling  over  the  earth's  surface  from  south  to  north 
cause  the  needle  to  fall  in  line  with  them  so  that  the  point  toward  the 
north  is  the  north  pole  of  the  needle,  and  vice  versa.  While  the 
magnetic  needle  is  made  to  serve  the  mariner  or  traveler  through  the 
compass,  it  may  be  made  to  serve  the  student  or  mechanic  in  indicat- 
ing polarity  of  magnets  for  him.  The  same  rule  is  operative  in  both 
cases. 

Permanent  Magnets. — The  magnetic  needle  retains  its  magnetism 
indefinitely.     This  is  because  it  is  made  from  a  high  grade  of  steel 


Fij?.  273.     Double  Magneto  Magnots.     Like  poles  together. 


Fig.  274.     Double   Magneto  Magnets.     I'lilike   j)oles   together. 

hardened  to  a  high  degree  of  temper.  Once  a  piece  of  hardened 
steel  is  magnetized  it  retains  its  magnetism  as  a  permanent  quality. 
It  is  thereafter  called  a  permanent  magnet.  Lines  of  force  flow  con- 
tinuously from  its  north  pole  to  its  south  pole  through  the  air  or 
other  medium.  In  a  good  magnet,  well  cared  for,  these  lines  of  force 
seem  to  lose  little  strength  from  year  to  year,  although  they  may 
be  performing  a  great  deal  of  work  as  in  the  case  of  the  magneto 
magnets. 


Fundamental  Electrical  Data 


273 


A  number  of  illustrations,  Fig.  269  to  Fig.  276,  show  the  flow 
of  the  magnetic  lines  of  force.  The  student,  in  studying  these,  will 
want  to  remember  that  like  poles  repel,  and  unlike  poles  attract. 
All  illustrations  were  made  with  iron  filings  sprinkled  over  a  glass 
or  directly  onto  the  magnets. 

Magnetizing  Steel  for  Permanency.  —  In  order  to  produce  a 
permanent  magnet  it  is  necessary  to  have  the  steel  first  formed  to  the 
desired  shape  and  then  hardened.  After  hardening  the  usual  method 
of  magnetizing  is  to  bring  the  ends  into  contact  with  a  powerful 
electro-magnet.  A  permanent  magnet  may  be  used.  The  lines  of 
force  flowing  through  the  body  of  the  steel  will  cause  certain  changes 
to  take  place  within  the  steel  which  result  in  the  steel  retaining  its 
magnetism,  thus  making  the  commercial  permanent  magnet. 


No.  275.  Two  stove  bolts 
serve  to  deflect  the  flux  in 
much  the  same  manner  as 
the  armature  core. 


Fig.  276.  Several  bolts  were  placed  be- 
tween the  pole  shoes.  Note  how  the  cen- 
ter of  the  field  is  built  up.  The  bolts 
serve  the  same  purpose  as  the  iron  in  the 
magneto  armature.  The  flux  follows  the 
metallic   path   rather   than   the   air   gap. 


The  Molecular  Theory. — The  theory  of  the  difference  of  the 
permanent  and  electro-magnets  is  one  of  the  nature  of  the  structure 
of  iron.  The  molecules  of  iron  or  steel  are  similar.  They  may  be 
said  to  have  a  certain  slight  freedom  of  motion  within  the  soft  iron, 
the  softer  the  iron  the  greater  the  freedom  of  motion.  On  the  other 
hand,  the  molecules  of  the  steel  have  been  fixed  in  position  by  the 
hardening  process,  having  no  power  of  themselves  to  move  into  posi- 
tion. 

In  magnetizing  either  metal  the  molecules  drop  into  line  with  the 
lines  of  force  because  of  the  force  of  the  magnetic  action.  In  other 
words,  the  student  may  consider  the  infinitely  small  particle,  the 
molecule,  as  having  two  ends.  One  end  becomes  a  north  pole  and 
the  other  end  a  south  pole.  Now  these  molecules  might  be  com- 
pared to  the  nails  formerly  mentioned.     The  north  pole  of  one  attracts 


2U 


Automotive  Trade  Training 


the  south  pole  of  another,  and  so  on  all  the  way  through  the  magnet. 
All  molecules  being  aligned  with  the  axis  of  the  magnet,  all  north 
poles  point  one  way  and  all  south  poles  of  these  molecules  point  the 
other  way,  until  one  end  of  the  iron  or  steel  bar  is  said  to  be  a  north 
pole  and  the  other  a  south  pole.  Instantly,  however,  the  outside 
mfluence  is  removed  the  molecules  within  the  soft  piece  of  steel  fall 
back  into  a  mixed  position  without  any  form  or  line  of  concerted 
action.  Not  so,  however,  with  the  hardened  steel.  These  molecules 
are  not  free  to  move  of  themselves.  The  magnetic  lines  of  force  as 
applied  changed  their  position  and  aligned  them  to  form  a  magnet 
and  they  will  retain  the  magnetism  permanently  simply  because  they 


&///)  or  Collector 


Fig.   277.     Simple   A.   C.   Motor  or   Generator, 

must  'retain  their  position  until  disturbed  by  some  outside  influence. 
This  theory  is  strengthened  by  the  fact  that  when  magnetizing  a  steel 
magnet,  jarring  it  with  a  block  of  wood  helps  to  increase  the  strength 
of  the  charge  taken.  Note  also  the  fact  that  jarring  a  magnet  in 
service  will  cause  it  to  lose  some  of  its  strength.  These  facts  would 
seem  to  indicate  that  the  molecules  being  disarranged  by  the  jar  fall 
out  of  line  and  the  strength  of  their  bit  of  magnetism  is  lost  to  the 
magnet  as  a  whole.  The  jarring  or  tapping  seems  to  help  the  mole- 
cules in  aligning  themselves  with  the  lines  of  force  when  charging 
and  to  help  them  fall  back  into  their  original  position  when  not  being 
charged. 

Saturation. — Steel  or  iron  always  reaches  a  point  where  no  more 
magnetism  may  be  put  into  it.  A  sponge  is  completely  saturated 
with  water  when  no  more  water  will  be  taken  up  by  it.  A  magnet  is 
completely  saturated"  when  no  more  lines  of  force  will  flow  through 


Fundamental  Electrical  Data 


275 


it  because  all  are  already  flowing  for  which  there  is  room.  While  this 
point  is  equally  true  of  either  type  of  magnet  it  has  a  peculiar  appli- 
cation to  the  electromagnet.  In  this  case  the  magnetism  is  induced 
by  the  current  flowing  through  the  wire  wrapped  on  the  core.  A 
slight  current  gives  slight  magnetism,  more  current  more  magnetism, 
and  so  on  until  the  saturation  point  is  reached  after  which  point  an 
increase  in  current  does  not  result  in  an  increase  in  magnetism  gen- 
erally speaking. 

Flux. — Magnetic    flux    or    field    is    the    condition    of    magnetisfn 
resulting  between  the  poles  of  a  generator  or  magneto  where  the  lines 


Pig.  278.     Simple  D.  C.  Motor  or  Generator. 

of  force  are  flowing.     Magnetic  lines  of  force  constitute  the  magnetic 
flux,  or  flux  as  it  is  commonly  called. 

Current  Generation. — The  student  has  seen  how  the  electric  cur- 
rent may  be  used  to  produce  magnetism  where  none  existed  before 
and  will  now  be  shown  how  the  reverse  may  be  accomplished.  If 
a  permanent  magnet  is  so  placed  that  a  loop  of  wire  may  be  mounted 
between  the  ends  of  it  and  caused  to  rotate  on  a  central  axis,  it  is 
made  to  cut  the  lines  of  force  or  the  magnetic  flux.  Cutting  these 
•lines  of  force  induces  current  in  the  wire.  This  current  will  flow 
trom  one  end  of  the  wire  toward  the  other  end  of  the  wire  and  if  slip 
nngs  and  brushes  are  provided  this  current  will  flow  from  wire,  to 
ring,  to  brush  and  oflf  into  an  external  circuit,  from  which  point  pro- 
vision must  be  made  to  return  it  to  the  other  slip  ring  and  internal 
circuit,    This  internal  current  will  continue  to  be  generated  as  long 


276  Automotive  Trade  Training 

as  the  wire  is  in  motion  and  an  external  circuit  provided  to  handle  it. 
Instead  of  two  slip  rings  only  one  may  be  used.  In  this  case  the 
other  end  of  the  wire  is  grounded,  as  is  also  one  end  of  the  external 
circuit. 

Internal  Circuits. — The  internal  circuit  is  that  formed  by  the  wire 
on  the  armature,  the  rings,  etc.  The  external  circuit  is  that  used  to 
perform  the  work  on  the  outside  as  lighting  the  lamps,  charging  the 
battery,  etc. 

Induction. — Whenever  a  loop  of  wire  is  made  to  cut  magnetic 
flux  it  causes  a  current,  or  sets  up  a  current  within  the  wire.  In  other 
words,  it  may  be  said  to  induce  a  current  to  flow.  The  process  is 
called  induction.  This  reversal  of  ends  in  contact  with  the  brushes 
has  the  effect  of  causing  the  current  in  the  external  circuit  to  flow 
always  in  one  direction.  Instead  of  having  two  pulses  of  current  in 
different  directions  for  each  turn  or  revolution  of  the  inductor,  there 
are  two  pulses  of  current  in  the  same  direction.  This  is  indicated  in 
Fig.  279.  To  the  beginning  student  it  may  seem  an  impossibility  to 
have  current  traveling  in  two  directions  over  the  same  wire  but  it 
does  not  travel  in  both  directions  at  the  same  time.  Current  travel 
is  very  rapid.  It  would  travel  nearly  eight  times  around  the  world 
in  one  second  so  reversal  may  be  said  to  be  almost  instantaneous. 
In  the  case  of  direct  current  it  is  not  one  continuous  even  flow  but 
might  be  compared  to  a  series  of  pulsations  following  one  another 
over  the  wire  in  the  same  direction,  while  the  pulsations  in  the  alter- 
nating current  flow  in  opposite  directions. 

By  increasing  the  number  of  coils  on  the  armature,  the  number 
of  bars  on  the  commutator  also  being  increased,  the  current  flow 
while  still  of  a  pulsating  nature,  is  far  more  steady.  This  is  due  to- 
the  fact  that  in  the  bi-polar  armature  there  are  two  zero  points.  From 
these  zero  points  to  the  peak  of  the  pulsation  and  down  again  to 
zero  as  illustrated  in  Fig.  279,  represents  one-half  revolution.  In  the 
next  half  revolution  the  same  effect  or  result  is  secured.  When  many 
bars  are  used,  it  is  only  when  the  current  is  approximately  at  its  peak 
that  the  brushes  are  in  a  position  to  take  it  off  to  the  external  circuit. 
Consequently  the  flow  of  current  in  the  external  circuit  is  at  the 
approximate  maximum  pressure  or  voltage  at  all  times. 

Armatures. — The  H  or  shuttle  type  of  armature  is  the  one  where 
the  slip  rings  are  used  resulting  in  an  alternating  current.  By  this 
is  meant  that  it  will  flow  first  in  one  direction  and  then  in  the  other 
through  both  circuits. 

Alternating  Current. — This  is  written  and  spoken  of  as  A.  C. 
current.  As  mentioned  above,  alternating  current  flows  first  in  one 
direction  and  next  in  the  reverse  direction.  When  cutting  the 
magnetic  flux  the  inductor  or  coil  is  brought  first  into  close  proximity 
to  the  north  and  the  south  poles.     In  the  next  half  revolution  that 


Fundamental  Electrical  Data  277 

portion  of  the  inductor  close  to  the  north  pole  is  brought  close  to  the 
south  pole,  and  the  part  which  was  close  to  the  south  pole  is  likewise 
brought  close  to  the  north  pole.  This  reversal  of  position  of  parts  of 
the  coil  or  inductor  results  in  reversal  of  the  direction  of  the  flow 
of  the  induced  current.  There  are  two  complete  reversals  of  cur- 
rent within  the  wire  each  complete  revolution  as  the  armature  is  kept 
turning.  A.  C.  current  is  quite  suitable  for  certain  classes  of  work, 
but  is  absolutely  unsuited  for  other  classes  as,  for  instance,  charging 
i?torage  batteries.  For  those  uses  requiring  direct  current  the  generat- 
ing machine  must  be  so  changed  as  to  produce  it. 


AfaximiWf  V(ilue  IweS^ 


TL 


/I  C  Current   l/Vayes 


Maxfmam  \/aJue  Lne 


.   D  C  Current  Wa)/es. 

Fig.  279. 

Direct  Current. — This  is  written  and  spoken  of  as  D.  C.  current. 
Current  coming  from  batteries  is  always  direct  current.  In  order  to 
generate  it  mechanically  the  slip  rings  must  have  a  commutator  sub- 
stituted for  them.  In  this  case,  as  in  the  simple  bi-polar  machine 
vv^ith  only  one  coil  and  two  segments  to  the  commutator,  the  separate 
ends  of  the  coil  are  each  brought  to  and  soldered  to  the  commutator 
segments.  These  segments  or  bars  are  separated  from  one  another 
by  some  form  of  insulator.  As  the  wire  loop  or  coil  is  turned  the 
end  attached  to  any  one  of  the  segments  is  brought  first  into  contact 
with  one  brush  giving  the  pulsations  from  zero  value  to  maximum 
value  each  half  turn.  This  is  equipped  either  with  slip  rings  for  A.  C. 
current  or  with  an  armature  for  D.  C.  current.  The  invention  of  the 
drum  type  armature  has  made  possible  the  steady  flow  of  current 
described  in  the  preceding  paragraph.  Illustrations  of  both  the 
shuttle  or  H  type  as  well  as  the  drum  type  are  shown  in  Fig.  266. 
The  student  will  be  interested  to  know  in  what  machines  each  is  used. 
This  information  will  appear  at  a  later  point. 


278 


Automotive  Trade  Training 


In  actual  generator  or  magneto  work  a  coil  of  many  turns  is 
substituted  for  the  single  loop  shown.  This  coil  is  wound  on  a  soft 
iron  core,  the  whole  being  mounted  on  a  shaft  in  its  center,  on  which 
it  is  revolved.  Either  one  or  two  slip  rings  are  used  while  for  the 
D.  C.  current  a  commutator  is  substituted.  In  the  drum  armature  a 
number  of  coils  are  used. 

As  stated  previously  the  voltage  depends  on  the  number  of  lines 
of  force  being  cut,  and  the  rapidity  with  which  they  are  cut.  For 
higher  voltage  the  speed  of  the  armature  must  be  increased  or  the 
number  of  turns  of  wire  increased. 

Commutator.  —  The   commutator   usually  has   as   many  bars   as 


Fig.  280.    Voltmeter. 


Fig.    281.     Ammeter. 


there  are  coils  on  the  armature,  although  at  times  two  coils  will  be 
attached  to  the  same  segment.  The  segments  or  commutator  bars 
are  insulated  from  each  other.  For  this  purpose  mica  is  the  standard 
material.  It  is  a  very  high  class  non-conductor.  Commutators  and 
slip  rings  being  subjected  to  wear  require  some  attention.  The 
matter  of  their  care  and  repair  is  treated  at  a  later  point. 

Field. — That  part  of  an  electric  machine  which  has  the  essential 
parts  so  arranged  as  to  produce  and  maintain  a  magnetic  flux  for  the 
armature  to  revolve  in  is  called  the  field  or  fields.  Usually  the  field 
is  stationary,  but  may  be  in  motion.  In  the  case  of  the  magnetos  the 
permanent  magnets  with  their  everflowing  lines  of  force  are  made  use 
of  in  building  up  the  field.  In  the  case  of  generators  the  electro- 
magnets constitute  the  field.  The  wires  or  conductors  are  called  the 
field  windings.     The  field  windings  in  modern  practice  are  mounted 


Fundamental  Electrical  Data 


279 


en  the  poles  themselves  although  at  times  they  may  be  found  on  the 
yokes  of  the  field  castings. 

Current  Control. — External  control  of  the  amount  of  current  fxow- 
ing  may  be  had  similar  to  the  control  of  other  sources  of  power. 
A  large  steam  pipe  is  needed  to  carry  steam  from  the  boiler  to  the 

locomotive     cylinders.       A     smaller  

pipe  is  needed  for  the  smaller  en- 
gine. The  pressure  per  inch  may 
be  the  same  in  either  case,  but  the 
amount  of  steam  flowing  through 
the  smaller  pipe  is  less  than  that 
flowing  in  the  larger  pipe.  The 
same  is  true  of  the  amount  of  work 
done. 

Similarly  in  the  case  of  the  cur- 
rent flowing  from  a  battery.  The 
larger  the  conductor  and  demand 
the  more  the  amount  of  current 
which  will  flow.  The  smaller  the 
conductor  the  less  the  amount  of 
current  which  will  flow  no  matter 
how  great  the  demand.  According- 
ly a  large  heavy  cable  is  used  to  con- 
nect the  starting  motor  which  may 
draw  up  to  300  amperes  momentarily  while  starting  the  engine  to 
turning.  The  voltage  or  pressure  can  be  no  more  than  that  of  the 
battery,  in  most  cases  six  or  twelve  volts.  For  lighting  and  ignition 
very  light  cables  are  used  as  the  current  consumption  is  seldom  over 
six  to  eight  amperes.  Necessarily  the  voltage  is  the  same  as  for  the 
work  consuming  the  greater  amount.  However,  even  these  lighter 
wires  or  lighting  cables  would  carry  a  great  amount  of  current  if 
there  were  not  provision  for  cutting  it  down.  Within  the  lamp  bulb 
the  filament  is  heated  because  of  its  natural  resistance  to  the  flow  of 
current.  The  student  is,  of  course,  familiar  with  the  fact  that  the 
filament  is  ordinarily  mounted  in  a  vaccum,  or  that  there  is  no  air  in 
the  bulb.  In  the  case  of  the  nitrogen  bulb  it  is  filled  with  nitrogen 
gas.  However,  in  either  type  the  filament  is  heated  by  its  resistance 
to  the  passage  of  current  until  the  bulb  is  made  to  glow  brightly. 
At  the  same  time,  however,  only  a  certain  amount  of  current  or 
amperage  can  pass  through  the  filament.  If  more  light  is  desired, 
more  filament  is  added.  This  necessarily  requires  more  current  to 
light  it  or  heat  it  to  an  incandescent  heat.  Larger  candle  power  bulbs 
«.lways  impose  a  heavier  drain  on  the  storage  battery.  This  is  just 
the  same  as  the  large  steam  cylinder  which  uses  more  steam  than  that 
on  the  engine  having  less  power  and  less  size  to  the  cylinder. 


Fig.    282.    Voltammeter,    a    combination 

instrument    for    measuring    either 

volts  or  amperes. 


Automotive  Trade  Training 


Resistance  Units. — While  the  lamp  bulbs  might  be  said  to  be 
resistance  units  serving  to  regulate  their  own  current  consumption 
vhrough  their  size,  other  units  of  automotive  equipment  are  supplied 
w^ith  separate  and  individual  resistance  units.  It  has  been  explained 
previously  that  all  metals  are  conductors  of  electricity.  Platinum, 
silver,  and  copper  are  the  best  conductors.  Iron  is  only  about  one- 
seventh  as  efficient  as  copper.  Certain  other  metals  are  even  much 
poorer.  Some  of  these  composed  largely  of  nickel,  michrome,  or 
German  silver  are  sold   under  the  trade   name   of   resistance   wire, 


Fig.  283.     Internal  mechanism  of  Electrical    Measuring    Instrument,    as 
voltmeter    or    ammeter. 

because  of  their  remarkable  resistance  to  the  passage  of  electric 
current. 

Ignition  units  or  coils  are  usually  provided  with  a  resistance  unit 
or  coil  which  protects  the  coil  winding  from  excessive  amperage  and 
consequent  damage.  It  serves  to  regulate  the  amount  of  current 
flowing  in  such  manner  that  the  spark  produced  is  approximately  the 
same  for  all  engine  speeds. 

A  quality  of  resistance  wire  to  be  remembered  is  that  the  resist- 


HiGH  Tension  TtRMihfiL 


Fig.  284.     Resistance  Unit  on  Coil. 


Fundamental  Electrical  Data 


281 


ance  to  the  passage  of  current  increases  with  the  amount  flowing. 
The  student  has  noted  in  the  case  of  the  lamp  bulb  that  it  is  resist- 
ance which  causes  the  filament  to  be  heated  and  glow.  In  the  case  of 
the  resistance  unit  this  is  also  true.  A  continuous  flow  of  current  will 
heat  the  resistance  unit.  As  it  heats,  its  resistance  increases.  The 
hotter  the  wire,  the  greater  the  resistance.  This  causes  the  cutting  off 
of  the  flow  of  current  at  least  partially,  and  this  in  turn  allows  the 
resistance  wire  to  cool  a  bit  when  more  current  starts  flowing  again. 
It  is  a  safety  valve  or  governor  for  the  coil.  This  feature  prevents 
the  ignition  coil  being  burned  up  when  the  ignition  switch  is  left  on 
and  the  engine  standing  still  with  contact  points  together. 

Fuses.— The  student  is  now  familiar  with  the  fact  that  electricity 
flowing  through  a  conductor  is  likely  to  heat  the  conductor.  The 
•imount  of  heat  developed  is  dependent  on  the  amount  of  current 
flowing,  as  well  as  the  size  of  the  conductor.  It  may  even  heat  the 
conductor  or  wire  to  a  point  where  the  insulation  will  be  burned  off, 
or  in  extreme  cases  melt  the  conductor. 


SIDE|OR 
DIMMER 

\ 


DASH^ 


BEAR 


Fig.  285.     Switches  with  Fuses  mounted  on  the  back. 


To  prevent  damage  to  expensive  units  of  equipment  practically 
all  systems  are  equipped  with  fuses.  The  fuse  is  a  protector.  If  an 
excessive  amount  of  current  flows  the  fuse  is  burned  out  or  melted 
out.  Fuses  are  made  from  metal  with  a  low  melting  point.  They 
are  designed  to  form  the  weakest  point  of  the  electrical  circuit  so 
that  there  will  be  no  doubt  about  which  part  will  be  burned  out  first. 
When  a  fuse  burns  out  it  opens  the  circuit  just  as  the  opening  of  a 
switch  would.  Thus,  a  unit  costing  a  few  pennies  is  made  to  protect 
one  costing  many  dollars.  Needless  to  say,  a  burned  fuse  should  be 
replaced  with  another  of  like  capacity.    Metals  which  cannot  be  burned 


282 


Automotive  Trade  Training 


out  should  never  be  substituted,  neither  should  very 
much  heavier  fuses  be  used.  The  trouble  causing 
the  fuses  to  burn  out  should  be  located  and  corrected 
before  replacing  the  fuse. 

Ground. — Presumably  from  the  fact  that  the 
earth  or  ground  is  used  for  return  circuits  in  many 
cases  of  electrical  installation,  or  for  the  protection 
of  others  from  over-charge,  has  come  the  practice 
of  terming  the  frame  or  superstructure  of  the  auto- 
mobile the  ground.  Automotively  speaking,  to 
ground  a  circuit  is  to  attach  one  end  of  the  wire 
forming  the  circuit  to  the  frame  or  other  metal  part 
of  the  car,  allowing  the  frame  to  act  as  the  return 
circuit.  A  magneto  may  have  one  end  of  the  pri- 
mary winding  or  internal  circuit  grounded  through 
the  bearings;  similarly  the  generator.  The  high 
tension  or  secondary  current  as  used  in  the  spark 
plugs  is  always  grounded.  One  terminal  from  the 
storage  battery  is  very  frequently  grounded  giving     oifc'i^t.  ^^Note^ailo 

method  of  ground- 
ing battery  to  car 
frame. 


what  is  constituted  the  one  wire  or  grounded  sys- 
tem. 


LOOSE 
CONNECTION 


Terminals  and  Poles. — The  polarity   of  a  magnet  is  dependent 
always  on  the  direction  of  the  flow  of  the  current  around  the  core. 

Reversing  the  direction  of  flow  of  current  in 
the  case  of  an  electro-magnet  will  reverse  the 
polarity  of  the  magnet.  If  no  magnetic  needle 
is  at  hand  to  determine  the  polarity  of  the 
magnets,  that  of  the  electromagnet  may  be 
determined  as  follows:  To  determine  the 
polarity  from  the  direction  of  flow  of  current, 
first  learn  the  direction  of  flow  of  current 
through  the  wire.  Next,  place  the  right  hand 
so  that  the  fingers  point  in  the  direction  of  the 
flow  of  current.  The  palm  of  the  hand  would  be 
next  to  the  coil.  The  thumb  pointing  at  right 
angles  to  the  hand  will  point  to  the  north  pole. 
Direction  of  Induced  Current. — To  deter- 
mine the  direction  of  the  flow  of  an  induced 
current  as  generated  in  a  magneto  or  genera- 
tor, or  the  positive  and  negative  terminals  of 
the  conductor  in  which  current  is  induced,  it 
is  necessary  first  to  determine  the  polarity  and 
direction  of  lines  of  force  or  the  magnetic  flux. 
Knowing  this,  set  the  thumb  of  the  right       id  to  point  in  this  direc- 


Fig.  287.    Open  Circuit  due 
to  Loose  Connection. 


Fundamental  Electrical  Data 


283 


Q    ^    @    ®    ®     ®        @ 

ICR.  <CR.         IgR.  IGR.  ICR.  ICR.  I^R. 

0.0  0.0  0  0    i 


HEAD  5  IDE 


•  ^ 


"-FUSES  — 


REAR     DASH  !      J*^'*^ 

LAMP    LAMP 


y  LIGHT  SWITCH  y 
*■>- CONTACTS    I 


5W1TCH  TERMINAL  I 


CO.  SHU  NT  WINDING- 
CUT  OUT  P01NT5- 
CaSERIES  WINDINC- 


w 


To  BATTERY 
I  IGNITION 


AMMETER" 


ETER\^/ 


-+  BRU5H 


-■wO* 


5TArV|NG 


SWITCH 


STARTING  MOTOR 


^^ 


OTD 


Fig.  288.     Technical  Wiring  Diagram. 


284 


Automotive  Trade  Training 


HEAD    LIGHT 


SIDE    LAMP 


I 


IF 


SIDE    LAMP 


„  .  .^.^  .,  ^■■.,....  -fc-L. 


BATTERY 


Fig.  289.    General  Wiring  Diagram. 


Fundamental  Electrical  Data  286 

tion.  It  should  also  be  at  right  angles  to  the  index  finger.  Next  set 
the  second  finger  at  right  angles  to  the  palm  of  the  hand,  and  pointing 
in  the  direction  of  the  conductor  travel  as  it  cuts  the  lines  of  force. 
The  index  finger  pointing  straight  indicates  the  direction  the  induced 
current  will  flow. 

Solenoid. — A  solenoid  is  a  coil  or  a  helix  of  wire.  It  might  be 
said  to  be  an  electromagnet  without  an  iron  center  or  core.  It  has 
the  general  characteristics  of  an  electromagnet  although  the  pull  will 
naturally  be  less.  The  magnetic  poles  north  and  south  are  in  evi- 
dence. The  south  pole  will  be  that  in  which  the  current  flows  in  a 
clockwise  fashion  when  the  observer  is  facing  it.  The  same  rule 
applies  to  electromagnets. 

Condenser. — It  has  been  learned  that  it  is  possible  to  store  up  a 
charge  of  electricity  which  may  then  be  drawn  off  for  use  in  perform- 
ing work.  The  storage  battery  is  a  device  used  for  this.  The  con- 
denser is  likewise  a  device  used  for  storing  current,  but  in  the  case 
of  the  condenser  there  is  no  chemical  action  and  in  most  cases  the 
charge  is  held  only  momentarily. 

The  condenser  is  made  up  of  paraffined  paper  and  tinfoil.  The 
paper  is  laid  between  the  layers  of  tinfoil  and  the  whole  wound  into 
convenient  form  and  pressed  into  the  desired  shape.  This  form  or 
shape  depends  on  the  housing  designed  for  the  condenser. 

The  capacity  of  the  condenser  depends  on  the  number  of  square 
inches  of  the  surface  of  the  dielectric  which  is  the  paraffined  paper. 
The  tinfoil  serves  to  conduct  the  current  to  and  distribute  it  over 
the  surface  of  the  dielectric  where  it  is  held. 

The  condenser  is  used  in  the  ignition  coil  circuit.  Its  action  is 
described  further  at  a  later  point. 


CHAPTER  11 

BATTERIES  AND  BATTERY  CARE 

As  indicated  in  the  previous  chapter,  the  storage  battery  can 
generate  Httle  or  no  electrical  current  or  energy  without  first  being 
subjected  to  a  charge  from  an  outside  source.  It  might  be  compared 
to  a  tank  for  storing  compressed  air.  A  stream  of  air  under  pressure 
is  forced  into  the  tank  until  the  gauge  registers,  say  100  pounds  per 
square  inch.  This  air  may  be  drawn  off  through  an  air  line  for  use 
in  inflating  tires.  After  one  tire  has  been  inflated,  there  is  less  pres- 
sure registered  on  the  gauge.  After  two  tires  are  inflated,  less  again, 
and  after  three  tires  still  less,  and  so  on.  Very  shortly,  unless  the 
compressor  is  started  to  work  and  the  tank  refilled,  the  pressure  will 
be  too  low  to  inflate  any  more  tires  properly. 


Fig.  290.     A  group  of  Starting  and  Lighting  Batteries.     (Cincinnati.) 

The  case  of  the  battery  is  very  similar.  If  the  starter  is  used 
frequently  the  battery  will  quickly  become  exhausted.  However 
electricity  is  not  stored  in  the  battery  as  air  is  stored  in  the  tank. 
The  same  air  which  is  run  into  the  tank  is  later  drawn  out  to  inflate 
the  tires.  In  the  case  of  the  battery  being  charged  the  current  flow- 
ing through  the  battery  drives  the  acid  from  the  plates  into  the  solu- 
tion. When  the  external  circuit  of  the  battery  is  closed  the  battery 
is  said  to  discharge.  That  is,  current  is  now  flowing  from  the  battery 
to  the  starter,  ignition,  or  lights.  This  current  being  taken  out  is  not 
the  same  as  went  into  the  battery  when  it  was  charged.  In  charging 
a  battery  the  current  flowing  into  it  sets  up  certain  chemical  action. 
When  the  external  circuit  is  closed  the  current  flowing  from  the 
battery  is  due  to  the  reaction  within  the  cells. 

Battery  Rating. — While  storage  batteries  are  rated  by  ampere 
hour  capacity  when  on  discharge,  we  find  that  automobile  starting 
and  lighting  batteries  are  given  the  capacity  rating  when  discharged 
at  the  five  ampere  rate.     Therefore,  a  battery  discharged  at  the  rate 

286 


Batteries  and  Battery  Care 


287 


of  five  amperes  for  twenty  hours  would  have  a  capacity  of  100  ampere 
hours.  As  the  rate  of  discharge  is  increased  the  ampere  hour  capacity 
is  lessened,  or  as  the  rate  is  decreased  the  ampere  hour  capacity  will 
be  increased.     For  example: 

The  100  ampere  battery  at  the  five  ampere  rate  would  have  a 
capacity  of  only  about  80  ampere  hours  when  discharged  at  ten 
amperes,  or  in  other  words,  it  would  discharge  at  ten  amperes  for 
eight  hours.  If  the  same  battery  were  discharged  at  one  ampere  it 
would  give  ofif  current  for  about  120  hours,  therefore  having  a  rate 
(if  120  ampere  hours.  It  will  be  seen  that  the  battery  could  be  com- 
pletely discharged  in  a  very  short  time  if  the  discharge  rate   were 

Filling  riuff 
Valve 

Level  of  Electrolyte 

Cell   Connector 

Sealing  Nut 
Post   Gasket 
Negative   Post 
Negative    Strap 


Postive   Post 
Positive   Strap 
Wood   Separator 

Positive   Plate 
Negative  Plate 

Rubber   Jar 
Wood  Case 


Fig.  291.     Battery   Cut  Away   to   Show   Construction. 

200  to  300  amperes  as  is  the  case  in  cranking  the  motor  with  the 
battery.  In  fact  the  discharge  rate  runs  even  higher  under  particu- 
larly unfavorable  starting  conditions.  Every  second  the  starting 
motor  is  running  means  great  drain  on  the  battery. 

The  student  will  note  likewise  the  fact  that  the  slow,  steady,  con- 
tinuous drain  as  that  of  the  Hghts  burning  with  the  engine  idle,  or 
ignition  switch  left  on  will  deplete  the  battery.  Automotive  engineers 
have  designed  the  generator  as  part  of  the  electric  system.  Its  duty 
is  to  send  the  current  through  the  storage  battery  and  cause  such 


888-  Automotive  Trade  Training 

electro-chemical  action  there  that  the  battery  is  always  ready  to  give 
off  energy  in  the  form  of  electric  current. 

Battery  Wear. — One  of  the  greatest  problems  meeting  the  battery 
manufacturers  is  that  of  educating  the  users  of  automobiles  and  other 
electric  equipment  with  reference  to  the  storage  battery.  An  air  tank 
may  be  charged  and  discharged  many  times  a  day  and  over  a  space 
of  many  years  without  showing  signs  of  depreciation.  Not  so  with 
fhe  battery.  Each  charge  and  discharge  produces  wear  within  the 
battery.  The  vibration  to  which  the  battery  is  subjected  contributes 
to  wear.  This  is  natural  wear  but  serves  nevertheless  to  shorten 
the  life  of  the  battery.  In  this  respect  the  battery  might  be  com.- 
pared  to  the  automobile  tire.  Every  turn  of  the  wheel  as  the  tire 
travels  over  the  road  means  one  turn  nearer  the  final  one.  So  much 
service  has  been  had  by  the  car  user.     Of  course,  the  user,  by  driving 


Fig.  292.     Storage  Battery  Name  Plate. 

carefully  and  keeping  proper  air  pressure  in  the  tire,  will  get  many 
miles  of  service  from  the  tire.  The  miles  of  service  bear  a  very 
direct  relation  to  the  amount  of  care  and  the  pressure  carried.  Just 
so  in  the  case  of  the  battery.  It  must  be  kept  fully  charged  so  as  to 
have  a  reserve  to  withstand  the  demands  made  upon  it  for  current. 
Careless  handling,  failure  to  provide  the  proper  amount  of  distilled 
water,  complete  discharge,  failure  to  bring  to  a  state  of  complete 
charge  and  like  faults  will  as  certainly  limit  the  service  a  battery  will 
give  as  running  a  tire  flat,  or  under-inflated,  will  limit  the  service 
the  tire  will  give.  The  user  of  the  battery  must  learn  to  care  for 
his  battery  as  he  has  learned  to  care  for  his  tires.  There  are  certain 
things  he  may  do  and  should  be  taught  to  do  by  the  battery  man. 
Then,  when  the  battery  has  served  its  life-time,  it  will  be  easier  for 
the  battery  service  station  to  deal  with  the  user.  He  will  understand 
that  the  battery  is  not  like  a  piece  of  steel  to  which  there  is  no  wear, 
but  rather  like  the  tire  it  returns  service  for  understanding  care. 

BATTERY  CONSTRUCTION 

Battery  Box. — The  battery  box  is  carefully  made  from  good 
wood.  It  is  designed  of  such  size  that  the  cells  will  just  fit  into  it 
with  room  for  proper  sealing.  Handles  are  attached  in  such  manner 
that  there  is  no  danger  of  the  screws  or  bolts  coming  into  contact 


Batteries  and  Battery  Care 


389 


with  the  jars,  in  a  manner  likely  to  break 

them.     The   bottom   of   the    box,   in    some 

instances,    is   provided   with    an    expansion 

joint  to  care  for  the  natural  expansion  and 

contraction  of  the  wood.     It  also  serves  the 

additional  purpose  of  allowing  any  moisture 

such  as  might  come  from  spilled  water  or 

electrolyte  getting  down  between  the  cells 

as  is  possible  in  certain  types  of  assembling. 

The  box  is  always  covered  with  acid  resist-       ^^^-  ^^-   battery  Box. 

ing  paint  to  protect  it  from  attacks  of  the  acid  in  the  electrolyte. 

Cell  Jars. — For  automotive  equip-  _^ 

ment  the  cells  are  always  made  of  a 
specially  prepared  hard  rubber.  This 
is  an  insulating  material  and  at  the 
same  time  will  stand  some  slight  strain 
without  breaking.  The  cells  vary  in 
size,  being  designed  to  just  receive  the 
element  when  it  is  fully  assembled. 
No  appreciable  movement  of  the  ele- 
ment within  the  cell  is  permissible  be- 
cause of  the  rapid  depreciation  and 
wear  which  would  occur.  The  bottom 
of  the  cell  has  ribs  moulded  across  it 
for  the  plates  to  rest  on.  The  space 
below  the  tops  of  these  ribs  receives 
the  sediment  from  the  plates  as  it  is 
worn  from  them. 

Element. — There  are  always  two  groups  of  plates  in  each  cell. 
These  are  insulated  from  each  other  by  means  of  the  separators. 


294.      Battery     Section.       Note 
Cell  Jar  Construction.    (Willard.) 


Fig.   295.     Complete 
Element.  (Exide.) 


Fig.  296.    Positive 
Plate. 


Fig.  297.     Negative 
Plate. 


One  group  of  plates  is  called  the  positive  and  the  other  is  called  the 
negative.  When  properly  assembled  and  insulated  with  the  separa- 
tors the  entire  assembly  is  called  an- element. 

Positive    Plates.  —  All    plates    are    built    up    of    socalled    active 


2:90  Automotive  Trade  Training 

material,  pasted  into  the  grid  which  is  the  frame  or  backbone  of  the 
plate.  The  grid  is  made  from  a  stiff  lead  and  is  so  molded  that  the 
itctive  material  is  held  in  between  light  bars  of  the  metal.  The  posi- 
tive plates  rriay'  lj>e  known  by  their  chocolate  color. 

Negative  Mates. — ^These  are  known  by  their  slatish  gray  color. 
The  active  material  is  pasted  into  the  same  type  of  grid  as  that  used 
for  the  positive  ones. 

Active  Material. — In-order  to  insure  the  rapid  and  ready  action 
of  the  active  material  pasted  into  the  plate  grids,  it  is  made  up  of 
lead  oxides  mixed  with  certain  other  materials.  Red  lead  is  mixed 
with  certain  other  materials  and  electrolyte  to  form  the  paste  for 
the  positive  plates.  The  litharge,  another  lead  oxide,  is  mixed  with 
certain  other  materials  and  electrolyte  to  form  the  paste  for  the 
negative  plates.  The  exact  composition  of  the  materials  and  the 
Droportion  of  each  kind  used  are  trade  secrets  which  are  carefully 
guarded.  Not  all  companies  use  the  same  formula,  nor  are  the 
methods  of  handling  the  plates  in  forming  the  same  in  all  cases. 
From  long  experimentation  each  company  has  arrived  at  the  best 
formula  for  its  own  purpose  and  that  best  suited  to  its  method 
of  manufacture. 

Forming  Plates. — As  suggested  above  the  methods  of  forming 
plates  are  not  the  same  in  every  instance.  All  green  plates  are  care- 
fully dried  before  forming.  The  forming  is  the  final  process  of  plate 
manufacture. 


Fig.   298.     Cell   Jar   Cover. 

One  method  of  forming  plates  is  as  follows :  After  the  plates 
are  pasted  and  dried,  they  are  placed  in  tanks,  positive  and  negative 
plates  alternately,  there  being  usually  about  80  plates  per  tank.  All 
positive  plates  in  each  tank  are  connected,  while  all  negative  plates 
are  similarly  connected.  The  negative  plates  of  one  tank  are  then 
connected  to  the  positive  plates  of  an  adjoining  tank,  there  being  only 
enough  tanks  in  the  circuit  so  that  the  voltage  from  the  plates  will 
not  exceed  the  voltage  of  the  charging  circuit.  The  tanks  are  filled 
with  a  low  density  of  electrolyte  which  covers  the  plates,  allowing 
Ihe  current  to  pass  from  plate  to  plate  during  the  forming  process. 

Another  method  of  forming  the  plates  is  as  follows:  After  the 
plates  are  pasted  and  dry  they  are  assembled  in  groups  by  lead  burn- 
ing, just  as  they  are  to  be  used  in  the  battery.  Next,  the  positive 
group  is  assembled  with  a  durrimy  negative  group,  with  separators 
between,  and  set  into  a  cell.    When  the  cell  has  been  filled  with 


Batteries  and  Battery  Care 


291 


1250  electrolyte  the  positive  group  is  connected  to  the  positive  lead 

from  the  charging  circuit  and  a  current  sent  through  the  element. 
This  forms  the  positive  plates  in  approximately  48  hours.  The  nega- 
tive group  is  assembled  with  a  positive  dummy  and  formed  in  the 
same  manner  excepting  the  time  required  which  is  72  hours. 

After  the  forming  process  is  completed  the  positive  plates,  due 
to  the  electro-chemical  action,  are  lead  peroxide,  while  the  negative 
plates  are  sponge  lead.  In  the  forming  process,  it  is  necessary  that 
the  plates  which  are  to  be  formed  into  positive  plates  be  connected 
to  the  positive  lead  of  the  charging  source. 

This  is  at  point  of  vital  significance  in  the  charging  of  a  battery. 
If  the  battery  is  put  on  the  line  with  the  negative  terminal  connected 
to  the  positive  lead  of  the  charging  equipment,  the  battery  plates  will 
have  to  be  reformed  before  the  battery  will  take  a  charge.  The 
change  is  certain  to  result  in  disaster  and  too  much  emphasis  cannot 
be  laid  on  the  matter  of  putting  the  battery  on  charge  correctly. 
Methods  of  determining  polarity  are  given  elsewhere  in  this  chapter. 

Separators. — The    separators    are    made    from    some    insulating 

material   such    as    specially    prepared   rubber    or    wood.     The    latter 

material  is  the  most  popular  with  manufacturers,  inasmuch  as  it 
is  the  cheapest  and  most  easily  handled.  How- 
ever, it  does  not  always  give  the  longest  service. 
Where  wood  is  used  the  acetic  acid  is  removed  to 
render  the  separator  impervious  to  the  attacks  of  the 
electrolyte.  This  special  treatment  also  leaves  the 
separator  porous  which  is  essential  to  all  separa- 
tors, as  it  allows  the  passage  of  the  electrolyte.  The 
separators  must  be  insulating  material,   otherwise 

short  circuits  would  be  developed  immediately  within  the  battery  and 

it  would  be  impossible  to  charge  it.     Whenever  the  insulators  wear 

out  or  break  down,   the   battery   will   develop   short   circuits   which 

prevent  it  taking  a  charge.   The  average  life  of 

a  set  of  wood  insulators  or  separators  is  about 

one    year.      Some    will    give    less    than    this 

amount  of   service  and  in  many  cases  more. 

Unusual  cases  of  three  and  four  years  are  on 

record.     The  rubber  insulators  and  separators 

such   as   the   Willard   Threaded   Rubber   as   a 

rule    give    considerably    more    service.      Here 

again  the  battery  might  be  compared  to  the 

tire.     A   fabric  tire,  while  well   worth   while, 

will  not  as  a  rule  give  as  much  service  as  the 

cord  tire.     This  does  not  mean  the  fabric  tire 

is  not  worth  the  money  invested  in  it  but  does  mean  that  the  greater 


Fig.    299. 
Wood   Separator. 


Fig.  300.  Wood  Separa- 
tors, worn  out  by  over- 
heating, undercharge  or 
overcharge. 


Automotive  Trade  Training 


amount  of  money  invested  in  the  cord  can  be  expected  to  make  a 
greater  return  to  the  user,  in  the  amount  of  service. 

Cell  Covers — One  of  the  hardest  problems  the  battery  manufac- 
turers have  had  to  solve  is  that  of  properly  securing  the  element  in 
the  cell  and  sealing  the  top  of  the  cell  so  that  the  electrolyte  is  not 
spilled  out  when  the  battery  is  in  service.  The  hard  rubber  cover  is 
designed  to  care  for  both  the  holding  of  the  element  in  position  and 
sealing  the  top  of  the  cell.  It  also  has  the  filler  cap  or  vent  plug 
fitted  into  it.  Holes  are  molded  into  it,  so  placed  that  the  posts  will 
come  up  through  them  and  permit  of  the  terminals  and  straps  being 
burned  on  above  the  cover.  The  cover  is  designed  always  with  the 
idea  of  perfect  sealing  in  mind.  Various  methods  are  used  by  the 
manufacturers,  and  the  student  will  need  to  understand  something  of 
this  construction  before  attempting  to  dismantle  any  particular  style. 

Sealing  Compound. — The  sealing  compound  is  a  tar  or  pitch- 
like  preparation  which  is  heated  in  a  pot  or  dipper  until  it  is  melted, 
when  it  may  be  poured  around  the  cell  covers  to  seal  the  jar  and 
cover  together.  It  is  also  used  in  certain  types  to  seal  the  posts  and 
to  seal  the  cells  into  the  box  thus  preventing  any  moisture  gettin-^ 
between  the  jars,  as  well  as  shaking  about  of  the  cell  jars  in  the  cas? 
or  battery  box.  The  sealing  compound  may  be  purchased  from  tho 
.supply  houses.  Directions  for  its  use  appear  at  a  later  point  in  this 
chapter. 


Fig.   301. 

Fig.  302. 

Fig.  30.3. 

Standard  Thimbla 

Standard  Taper 

Straiglit    Clamp 

Type  Terminal. 

Plugs  and 
Screw. 

Lug    Terminal. 

Terminals  and  Straps. — There  is  some  difference  in  the  style  ot 
terminal  used  by  the  battery  manufacturers  and  car  builders.  The 
corrosive   effects   of   acid   make   it   necessary   to   lead   coat   all   brass 


Fig.    .304. 
('oil    Connector. 


parts  or  make  the  entire  terminal  from  lead  alloy.     Figs.  301  to  303 
show  some  of  the  most  popular  forms  in  use.     The  prime  requisite 


Batteries  and  Battery  Care  293 

in  their  use  is  cleanliness  which  is  best  secured  through  the  use  of  a 
baking  soda  solution  used  to  clean  them  and  neutralize  the  acid. 
This  prevents  the  terminals  from  being  constantly  enlarged  as  is  the 
case  where  a  knife  blade  is  used  to  scrape  them  clean.  Do  not  allow 
any  of  the  cleaning  solution  to  get  into  the  cells.  Fine  sandpaper  is 
often  used  to  advantage.  When  properly  cleaned  a  thin  coat  of  vase- 
line or  light  cup  grease  will  serve  to  protect  them. 

The  straps  or  connectors  are  used  to  join  the  negative  post  of 
one  cell  to  the  positive  post  of  another  cell.  These,  like  the  terminals, 
are  usually  attached  by  burning  them  to  the  posts. 

BATTERY  CARE 

As  suggested  previously  proper  care  of  the  battery*  is  essential 
to  service.  Even  with  proper  care  there  is  a  limit  to  the  normal  Hfe 
of  the  battery.  Neglect  of  the  two  fundamentals,  a  proper  charge  and 
the  addition  of  distilled  water  always  materially  limits  the  life  of  the 
battery. 

Distilled  Water. — Every  storage  battery  is  dependent  on  the. 
electrolyte  surrounding  the  plates  for  its  electro-chemical  action. 
Electrolyte  is  made  up  of  two  elements  or  liquids,  water  and  sul- 
phuric acid.  The  acid  is  not  subject  to  evaporation.  The  water  is. 
This  accounts  for  the  fact  that  acid  does  not  need  to  be  added  to  a 
battery  to  bring  the  solution  up  to  the  proper  level,  while  it  is  neces- 
sary to  add  water  at  regular  intervals. 

Only  pure  or  distilled  water  should  be  added  to  the  solution  since 
w^ater  bearing  any  impurities  will  introduce  them  into  the  battery 
where,  due  to  the  chemical  action,  they  may  do  serious  harm.  Metal 
vessels  or  containers  should  not  be  used  for  the  distilled  water.  In- 
stead, glass  or  glazed  earthenware  should  be  used.  It  may  be  secured 
from  the  supply  houses  or  drug  stores.  In  adding  distilled  water  the 
plates  within  the  cell  should  be  covered  to  approximately  one-half 
inch  above  their  tops.  The  electrolyte  should  not  be  permitted  to 
drop  below  the  top  of  the  plates  at  any  time.  Water  added  to  a 
battery  remains  separated  only  so  long  as  it  may  be  necessary  for  the 
motion  of  the  car  and  the  charging  action  of  the  generator  current 
to  mix  it  with  the  electrolyte.  For  this  reason  some  care  must  be 
used  in  adding  the  water  in  the  winter  time.  In  this  case  it  should 
be  added  just  before  the  car  is  to  be  operated  so  that  the  water  and 
electrolyte  may  be  thoroughly  mixed.  In  case  of  any  water  being 
spilled  on  the  battery  top  it  should  be  dried  with  a  cloth.  To  prevent 
spilling  when  filling  use  a  syringe  or  glass  funnel.  It  frequently 
happens  that  a  battery  which  has  been  filled  carelessly  will  become 
discharged  without  apparent  reason.  This  is  due  to  the  fact  that  the 
spilled  water  and  electrolyte  have  established  a  short  circuit  throti^h 
which  the  battery  discharges  as  fast  as  the  generator  charges  it. 


294 


Automotive  Trade  Training 


Battery  Freezing. — This  is  not  likely  to  happen  even  in  extreme 
temperatures  if  the  battery  is  properly  charged.  Sulphuric  acid  will 
not  freeze.  Water  will  freeze.  By  keeping  the  two  mixed  in  the 
form  of  electrolyte  the  water  will  not  freeze.  As  stated  previously, 
however,  when  the  battery  is  discharged  the  acid  has  practically  all 


tl     mZM: 


t.l.t.i.i.i.l.l.lX"^ 


)CD 


Fig.  305.     Hydrometer. 


entered  into  the  plates.  This  leaves  only  the  water  surrounding 
them,  consequently  the  reason  for  a  discharged  battery  freezing  is 
evident.  Bringing  the  battery  to  a  full  charge  will  drive  the  acid 
out  of  the  plates  into  the  water  again,  thus  bringing  the  electrolyte 
up  to  its  proper  strength.     The  specific  gravity  of  a  fully  charged 


Fig 


Using   Hydrometer   to    Test   Battery. 


battery  will  read  between  1.275  and  1.300.     At  this  point  it  will  not 
freeze   except   at   extremely   low   temperatures   as   approximately  80 


Batteries  and  Battery  Care 


295 


.1300 


degrees  below  zero.  On  the  other  hand  a  fully  discharged  battery  will 
freeze  at  zero  or  above.  Hence  the  necessity  of  keeping  well  charged 
during  the  cold  winter. 

Testing  Battery. — The  reliable  test  to  use  in  judging  the  state  of 
charge  of  a  battery  is  the  hydrometer  test.  Just  as  the  scales  will  show 
that  a  piece  of  lead  will  weigh  more  than  the  same  size  of  a  piece 
of  aluminum  and  not  only  that,  but  the  exact  difference  in  weight, 
so  the  hydrometer  will  show  the  weights  of  liquids.  Water  is  taken 
as  the  standard  fluid  and  all  other  liquids  are  judged  as  they  are  heav- 
ier or  lighter  than  it.  For  the  sake 
of  a  starting  point  water  is  said  to 
have  a  specific  gravity  of  1.000. 
Sulphuric  acid  is  almost  twice  as 
heavy  having  a  specific  gravity  of 
1.835. 

Hydrometer  Reading. — With  a       M  B^J-HSO 

little  practice  the  hydrometer  is  read- 
ily used  and  properly  read.  In  tak- 
ing the  specific  gravity  of  the  bat- 
tery it  is  placed  with  the  rubber 
tube  end  in  the  electrolyte  having 
first  deflated  the  bulb.  Next  care- 
fully release  the  pressure  on  the 
bulb  and  the  electrolyte  will  be 
drawn  up  into  the  body  of  the  in- 
strument. In  this  portion  of  the 
instrument  is  placed  the  hydrometer 
proper,  the  other  parts  really  being 
a   syringe   arrangement.     With   the 

electrolyte  in  the  body  of  the  syring.  '^''tuSf-.^ll^m^^o)  '1^'^Ts- 
the     hydrometer     will     float.       The  .  charged   (iiso) 

more  nearly  the  battery  is  to  a  full  charge  the  higher  the  hydrometer 
will  float.  The  graduations  are  read  at  the  upper  level  of  the  elec- 
trolyte. To  do  this  properly  it  is  necessary  to  bring  the  level  of  the 
eye  even  with  the  level  of  the  liquid  within  the  hydrometer.  It  is 
also  necessary  to  see  that  the  hydrometer  is  actually  floating,  without 
the  top  touching  the  upper  end  of  the  chamber  or  the  bottom  resting 
on  the  bottom  of  the  chamber  in  which  it  is  contained.  After  the 
electrolyte  has  been  drawn  into  the  instrument  to  the  proper  level 
to  float  the  hydrometer  nicely,  a  little  pressure  should  always  be  given 
the  bulb  to  relieve  any  vacuum  in  the  upper  part  of  the  chamber, 
otherwise  the  reading  will  be  too  high. 

On  the  hydrometer,  or  within  it,  appear  the  graduations  which 
are  used  to  indicate  the  state  of  charge.  These  graduations  usually 
run  from  1.150  to  1.300.     The  first  figure  indicates  complete  exhaus- 


for 


^96  Automotive  Trade  Training 

tion  or  discharge.  The  second  figure  means  that  the  battery  is  fully 
charged  if  the  hydrometer  is  carried  by  the  electrolyte  with  this  point 
even  with  the  surface.  It  is  the  practice  of  the  hydrometer  manu- 
facturers to  mark  the  instrument  for  the  vital  points. 

A  gravity  reading  of  1.150  indicates  fully  discharged. 

A  gravity  reading  of  1.220  indicates  half  charged. 

A  gravity  reading  of  1.280  indicates  fully  charged. 

The  student  will  understand,  as  he  becomes  familiar  with  bat- 
teries and  methods,  of  judging  tl;ieir  condition,  that  it  is  possible  to 
have  a  battery  fully  charged  at  readings  either  above  or  below  the 
figures  given  depending  on  the  original  strength  of  the  electrolyte. 
This  is  explained  fully  in  the  following  paragraph  covering  battery 
charging. 

Battery  Charging  While  in  Service. — The  owner  should  either 
inspect  his  battery  with  reference  to  water  and  state  of  charge  at 
legular  intervals,  or  take  the  car  to  the  service  station  where  the 
work  is  generally  done  free  of  charge.  If  the  battery  is  maintained 
between  the  points  of  1.250  and  1.275  by  the  generator  it  is  an  indica- 
tion that  the  system  is  properly  adjusted  for  the  type  of  service 
expected  of  that  particular  car.  If  the  battery  shows  a  continued 
tendency  to  become  exhausted  it  should  be  given  a  special  charge.  If 
this  does  not  remedy  the  trouble  and  the  battery  is  in  good  condi- 
tion, the  charging  rate  should  be  adjusted  to  give  a  higher  output 
from  the  generator.  Care  must  be  used  not  to  exceed  the  rated  out- 
put of  the  generator  or  to  injure  the  battery  by  an  excessive  charge 
rate. 

If  the  battery  shows  a  tendency  to  become  overcharged  the 
charging  rate  should  be  lowered,  or  if  the  trouble  is  thought  to  be 
cf  a  temporary  nature  the  lamps  may  be  burned  in  the  day  time  or 
while  the  car  is  housed  in  the  garage  over  night  to  reduce  the  charge 
and  the  specific  gravity.  The  same  result  may  be  obtained  more 
quickly  by  operating  the  starting  motor  for  a  short  time,  say  from 
three  to  eight  minutes.  The  slower  discharge  is  the  better.  For 
summer  touring  extreme  care  must  be  used  to  prevent  overcharging 
and  breaking  down  the  battery  due  to  overheating.  Overheating 
causes  the  plates  to  become  buckled  and  the  active  material  to  be- 
come loosened  from  the  grid. 

Again  the  battery  may  be  compared  to  the  pneumatic  tire  in  that 
the  hydrometer  shows  the  amount  of  current  in  the  battery  as  the 
tire  gauge  shows  the  amount  of  air  in  the  tire,  Using  a  battery  when 
it  is  nearly  exhausted  is  just  as  bad  as  running  a  tire  with  very  low 
pressure  over  a  rough  street.  Putting  an  excessive  amount  of  air 
into  a  tire  is  very  likely  to  produce  disastrous  results.  When  the  tire 
blows  out  it  may  be  beyond  repair.  Overcharging  a  battery  is  likely 
to  do  the  same  for  it.     When  it  finally  fails  it  is  ruined  beyond  repair. 


Batteries  and  Battery  Gare 

HOW  TO  RECOGNIZE  BATTERY  FAULTS  AND  GOOD  AND 
DAMAGED  BATTERY  PARTS 

As  indicated  previously,  natural  wear  and  usage  limit  the  life  of 
the  battery.  Abnormal  usage  makes  the  life  of  the  battery  very  short 
in  many  cases.  How  to  detect  incipient  cases  of  trouble  and  correct 
them  was  mentioned  in  the  previous  section  of  this  chapter. ,  To 
detect  and  remedy  the  more  serious  cases  of  trouble  is  the  work  of 
the  battery  service  station.  In  most  cases  this  means  the  opening 
of  the  cells  to  permit  of  visual  inspection  of  the  plates  and  separators. 
Tests  Which  Indicate  the  Need  of  Opening  the  Battery. — If  a 
battery  refuses  to  take  a  charge  or  runs  down  in  a  short  time  after 
having  been  charged  the  indications  are  those  of  internal  trouble.  If 
the  battery  runs  down  quickly  when  in  position  on  the  car,  but  holds 
a  charge  when  charged  separately  and  left  oflf  the  car,  the  trouble  is 
likely  with  the  external  car  circuit  which  should  be  inspected  for 
grounded  or  short  circuited  leads.  Tests  for  determining  trouble  in. 
the  starting,  lighting  and  ignition  circuits  are  given  in  Chapters  12 
to  15. 

If,  however,  the  battery  will  not  hold  a  charge  even  when  oflf  the 
car  no  more  time  should  be  lost  before  it  is  opened  and  inspected. 
Inspection  will  show  whether  it  is  advisable  to  repair  or  not. 

If  a  battery  is  known  to  have  been  frozen  it  is  advisable  to  open  it. 
If  a  battery  has  been  overheated  it  is  advisable  to  open  it  up. 
If  the  electrolyte  shows  red  or  muddy  it  is  an  indication  that 
the  active  element  is  dropping  from  the  grids.     The  battery  should 
be  opened  for  inspection. 

If  the  battery  has  one  or  two  cells  which  are  always  lower  in 
point  of  gravity  reading  and  water  level  it  is  an  indication  that  the 
cell  jar  is  leaking.  If,  however,  the  cell  which  always  has  the  low 
solution  level  shows  the  highest  gravity  reading,  it  is  possible  that 
the  heat  of  the  higher  charge  is  evaporating  more  water  from  it  than 
from  the  others. 

If  the  crack  in  the  jar  is  large  the  loss  o: 
electrolyte  is  evident  from  the  fact  that  the 
battery  box  and  container  are  wet,  as  well  as 
the  fact  that  the  electrolyte  cannot  be  main- 
tained at  the  proper  level. 

The    methods    of    opening    batteries    are 
described  at  a  later  point.     Before  proceeding 
with  that  and  actual  repair  methods,  the  stu- 
Fip.    308.     Negative       dent  should  know  how  to  recognize  plate  con- 

Plates    Sulphated    from  j:^:^^  ^„a  ,r«1,,^ 

too  low  a  level  of  Eiec-       dition  and  valuc. 

*^"^y^*^-  Sulphation. — In    the    mind    of   the    novice 

the  term  sulphation  means  a  condition  which  is  certain  to  ruin  the 


Automotive  Trade  Training 

battery.  This  is  not  always  the  case,  by  any  means,  since  the  normal 
action  of  the  battery  is  dependent  on  sulphation.  When  a  battery  is. 
discharged,  or  rather  when  the  chemical  action  within  the  battery, 
which  is  responsible  for  the  flow  of  surrent  from  the  battery,  is  going 
on,  the  sulphuric  acid  or  sulphur  within  the  electrolyte  is  leaving  it 
and  entering  the  plates  causing  sulphation.  When  the  battery  is 
charging,  the  sulphuric  acid  is  being  driven  out  of  the  plates  leaving 
the  positive  plates  lead  peroxide,  and  the  negative  plates  sponge  lead. 
The  current  production  of  the  battery  is  dependent  on  normal  sul- 
phation. 

Lack  of  a  full  or  proper  charge  allows  the  plates  to  sulphate  abnor- 
mally or  to  an  excess  degree.  When  this  condition  obtains  the  plates 
become  coated  with  a  grayish  substance,  which  covers  the  surface 
sealing  the  pores,  thus  destroying  in  part  the  activity  of  the  cell. 
This  is  evident  if  a  voltage  reading  is  taken.  In  a  badly  sulphated 
cell  the  voltage  drops  off  very  materially.  A  cell  or  battery  which 
has  been  left  for  some  time  in  a  badly  sulphated  condition,  which  is 
the  case  in  partially  or  wholly  discharged  batteries,  is  very  difficult  to 
charge.  The  acid  in  the  plates  has  sealed  them  and  it  is  hard  for  the 
electric  current  to  drive  it  out  in  charging. 

Sulphation  may  be  due  to  a  low  electrolyte  level  which  has  per- 
mitted the  upper  part  of  the  plates  to  stand  above  the  solution  as 
well  as  to  the  lack  of  proper  charge.  Fig.  308  shows  sulphation  due 
to  too  low  a  solution  level. 

Overheated    Plates.  —  Charging    a    badly 
sulphated   battery   at   other   than   a   very:  low 
rate  is  practically  certain  to  cause  the  plates  to 
buckle  and  warp.     In  some  cases  the  force  is 
sufficient  to  break  the  cell  jars  and  loosen  the 
covers.     This  is  due  to  the  rapid  and  unequal 
expansion  of  the  active  element.    Unless  suffi- 
cient time  is  given  for  the  strains  to  be  neu- 
Fig.  309.    Warped  piatea      tralized  within  the  active  material  itself  warp- 
ing  is   certain   to   result.      Fig.   309   shows   a 
group  of  warped  plates. 
Damaged  Separators. — It  is  seldom,  if  ever,  advisable  to  use  old 
wood  separators  the  second  time.     It  is  far  better  to  replace  them 
with  new  ones  inasmuch  as  a  cheap  unit  is  made  to  protect  the  plates 
which  are  the  expensive  parts  of  a  battery.     In  the  case  of  separators 
such  as  the  Willard  Threaded  Rubber  and  certain  other  ones,  it  is 
possible  to  use  them  as  long  as  they  are  not  damaged  in  any  way 
such  as  being  cracked  or  torn,  or  if  they  are  not  worn  through  from 
use  between  the  plates.     As  stated  before,  the  separator  must  be  an 
insulator  as  well.     If  all  or  part  of  a  separator  is  missing  from  its 
position   between   the   plates  there   is   certain   to   be   a   short   circuit 


Batteries  and  Battery  Care 


29» 


developed  at  that  point.  It  is  just  as  though  two  wires  carrying 
current  were  permitted  to  touch  each  other.  Fig.  300  shows  the  effect 
of  wear  and  usage  on  wood  separators. 

Frozen  Plates. — The  plates  from  a  battery  which  has  been  badly 
frozen  are  readily  recognized  by  the  fact  that  there  is  little  left  but 
the  grids.  The  active  material  falls  from  the  positive  plates  in 
chunks.  In  other  words,  the  active  material  with  which  the  grids 
were  pasted  is  all  falling  or  has  fallen  out  of  them.  In  this  respect 
it  resembles  the  plate  which  has  been  subjected  to  continuous  over- 
heating and  overcharging.  The  overheated 
plate  disintegrates  a  bit  more  naturally  than 
the  frozen  one.  Knowledge  of  conditions  of 
service  will  help  the  student  to  differentiate 
between  the  two. 

Judging  the  Value  of  Positive  Plates. — If 
the  active  material  is  practically  all  in  place 
and  seems  fairly  hard  when  tested  with  the 
blade  of  a  knife,  Fig.  v310,  the  plate  will  give 
enough  additional  service  to  warrant  the  ex- 
pense of  reinsulating  and  reassembling.  However,  if  the  active 
material  is  loose  and  considerable  of  the  surface  gone  it  is  best  not 
to  use  it. 

Judging  the  Value  of  Negative   Plates. — Negative   plates   very 
seldom    wear    out    before    the    positive    group.     Sulphation    is    more 


Fig.  310.     Testing   a   Posi- 
tive Plate. 


Fig.    312.      Terminals 
damaged  from  Corrosion. 


Fig.   311.     Straightening   Plates. 

marked  in  their  case.  A  slow  charge  will  usually  remedy  this.  Care 
should  be  used  to  keep  the  negative  groups  from  unnecessary  expos- 
ure to  the  air.  If  left  exposed  to  the  air  for  more  than  an  hour  the 
negative  plates  dry  out,  heat  and  harden. 

If  necessary  to  leave  the  battery  in  a  dismantled  condition  the 
separated  groups  should  be  left  in  water  or  weak  electrolyte. 

Judging  the  Value  of  the  Battery  Case.— Unless  the  case  shows 


aoo 


Automotive  Trade  Training 


signs  of  rotting  around  the  upper  edges  it  is  usually  sound.  The 
rapid  depreciation  of  some  cases  is  due  to  the  electrolyte  being  spilled 
on  them.  The  acid  in  the  electrolyte  attacks  the  wood  once  it  has 
penetrated  the  paint.  The  case  should  always  be  cleaned  and  painted 
with  asphaltum  or  other  acid  resisting  paint,  both  on  the  inside  and 
the  outside.  If  in  a  state  of  saturation  from  the  acid  the  case  should 
first  be  washed  in  a  baking  sOda  solution,  after  which  it  is  permitted 
to  dry  before  painting. 

Judging  the  Value  of  Jars  and  Jar  Covers. — The  hard  rubber  jars 
are  subject  to  physical  dam a,c:c  from  blows  as  from  the  sudden  drop- 


m. 


Pig.    313.     Battery    Covered    with    Wet    Cloth    before   Lead  Burning. 

ping  of  the  battery.  Heating  the  jar  in  boiHng  water  leaves  it  a  bit 
more  pliable  and  this  is  sometimes  advisable  in  assembling.  The 
least  sign  of  a  flaw  should  be  sufficient  to  cause  the  jar  to  be  dis- 
carded. The  covers  are  very  frequently  damaged  in  the  process  of 
disassembling  a  battery,  especially  those  which  have  the  element  in  a 

buckled  condition.  Wherever  this  is  the 
case  the  damaged  cover  must  be  replaced 
with  a  new  one. 

JOB     101.     OPENING    BATTERIES     FOR 
INSPECTION    AND    REPAIR 

Removing    Connecting    Straps    and    Term- 
inals.— While  the  construction  of  batteries  differs 
somewhat,  practically  all  types  have  the  connect- 
ing straps  and  the  terminals  burned  to  the  group 
posts.     Consequently   in    opening   a   battery   the 
first  thing  to  do  is  to  centerpunch  a  hole  in  the 
exact    center    of    each    terminal    and    connector 
head.     The  next  step  is  to  drill  each  of  the  con- 
Fig.  314.  nectors  and  terminals  as  indicated  in  the  illus- 
tration Fig.  314.     This  work  may  be  done  with  the  brace  but  where  there  is 
considerable  to  be  done  the  usual  practice  is  to  install  a  light  power  drill  with 


Batteries  and  Battery  Care 


301 


adjustable  stop  so  that  the  holes  may  be  drilled  quickly  and  to  a  uniform  depth. 
Where  there  is  a  power  drill  available  for  general  service  this  is  frequently 
used.  The  depth  to  which  the  hole  is  drilled  will  vary  from  Y^"  to  Y^".  If  the 
connectors  do  not  come  loose  after  drilling  to  thi^  depth  they  may  be  loosened 
with  the  lead  burning  flame.  While  applying  the  flame  have  the  strap  gripped 
with  a  pair  of  pliers  and  lift  as  the  lead  is  softened.  Usually  no  heat  is  needed 
as  the  straps  will  lift  off  easily. 

Softening    Sealing    Compound    Around    the    Covers. — There    are    three 
methods  of  doing  this  work.     Formerly  the  method  illustrated  in  Figs.  315  and 


Pig.  315. 
316  was  used  to  a  considerable  extent.     More  recently  the  steam  boiler  with  its 
individual  tubes  for  each  cell  has  met  with  much  favor  in  the  service  stations 
and   repair  shops.     Where  the 
amount  of  work  handled  is  not 
so  great  the  gas  flame  is  used. 

Hot  Water  Method.— The 
top  of  the  battery  should  be 
thoroughly  cleaned  of  lead 
borings  and  dirt  after  which 
the  vent  plugs  are  removed. 
The  battery  is  placed  upside 
down  on  the  wash  trough  Fig. 
315  and  the  electrolyte  allowed 
tQ  drain. 

A  tank  of  hot  water  is  provided.     This  may  be  a  large  pan  heated  over  the 
gas  flame.     There  should  be  sufficient  water  to  come  to  a  point  at  least  2"  over 


316. 


Fig.  317. 


Fig.   318. 


302 


Automotive  Trade  Training 


the  sides  of  the  case.  If  the  water  is  boiling,  five  minutes  will  leave  the  com- 
pound soft  enough  to  work.  The  battery  may  now  be  placed  on  its  side  on  the 
table,  and  while  holding  with  one  hand  the  workman  gives  a  series  of  pulls  on 
the  posts,  using  a  pair  of  gas  pliers  and  alternating  from  one  post  to  the  other 
until  the  element  of  that  cell  is  broken  loose  and  pulled  out.     Refer  to  Fig.  317. 

Steam  Method. — If  the  entire  battery  is  to  be  opened,  the  vent  plugs  are 
removed  and  the  steam  jets  are  placed  one  in  each  vent.  It  is  not  necessary 
to  remove  the  electrolyte  in  this  case.  Allow  the  steam  to  flow  until  the 
compound  over  the  covers  is  quite  soft.     Refer  to  Fig.  318. 

After  the  compound  has  softened  the  elements  may  be  lifted  from  the  cells 
as  indicated  in  Fig.  319.     Use  gas  pliers  to  grip  the  posts.     If  the  battery  is 


Fig.  319. 
held  in  a  vise  the  work   is   made   easier.     If  no   vise   is  available   it   may  be 
necessary     to  place  the  battery  on  the  floor  and  hold  it  with  the  foot  while 
pulling  on  the  posts. 

Gas  Flame  Method. — With  an  ordinary  gas  flame  heat  the  compound 
around  the  edges  of  the 
cover.  It  is  necessary  to  keep 
the  flame  moving  so  that  the 
cover  is  not  burned.  The 
compound  should  be  removed 
with  a  narrow,  heated  chisel. 
In  doing  the  work  in  this 
manner  the  operator  contin- 
ually heats  the  chisel  with 
the  gas  flame  to  prevent  the 
compound  from  sticking  to 
it,  and  assist  in  speeding  up 
the  work.  If  a  flame  is  used 
it  should  be  yellow  since  this 
is  not  as  hot  as  the  blue  flame 
from  the  lead  burning  torch. 
If  no  other  flame  is  available, 
the  heat  from  a  gasoline 
torch  may  be  used  but  this  is  Fig.  320. 

an     operation     requiring    extreme  care.     Refer  to  Fig.  320. 

Since  the  steam  boiler  outfit  is  to  be  preferred,  it  is  well  for  the  operator 


Batteries  and  Battery  Care 


303 


Fig.    321. 


to  provide  himself  with  a  boiler.     If  nothing  else  is  available,  an  old  can  or  tea 

kettle  may  be  used.  The  tubes  used  to  convey 
the  steam  are  rubber.  In  the  case  of  the  tea 
kettle  they  m^y  be  attached  to  the  spout. 
Since  no  pressure  is  required  the  lid  will  be  all 
the  cover  necessary.  It  also  serves  as  a  safety 
valve. 

Cleaning  Parts  of  Compound. — With  a 
putty  knife  or  chisel'all  the  surplus  compound 
should  be  removed  from  the  covers  and 
around  the  posts.  Be  certain  to  get  every  part 
quite  clean.  The  method  of  cleaning  the  post 
wfell  with  a  screw-driver  is  shown  in  Fig.  321. 
Remove  any  compound  from  the  top  inside 
edges  of  the  jars  as  shown  in  Fig.  322.  If  this 
is  not  done  trouble  will  be  experienced  in  refit- 
ting the  element  and  cover. 

Removing  Sediment. — As  explained  in  the  forepart  of  the  chapter,  as  the 
active  material  wears  a  sediment  collects  at  the 
bottom  of  the  cell  jar  between  the  ribs  on  which 
the  element  rests.  To  clean  this  sediment  out 
of  the  jar  the  box  is  placed  on  the  washstand  and 
a  stream  of  water  is  thrown  into  it  which  washes 
all  the  parts  clean.     Refer  to  Fig.  323. 

Care  of  Elements  and  Electrolyte, — When 
the  element  is  first  withdrawn  it  may  be  set  on  top 
of  the  jar,  as  shown  in  Fig.  324,  where  it  is  al- 
lowed to  drain.  When  thoroughly  drained  it  is 
separated  for  inspection  and  repairs.  The  elec- 
trolyte should  be  tested  for  specific  gravity  in 
order  that  less  trouble  is  experienced  in  re- 
charging when  refilled  after  the  repairs  are  made. 
The  old  electrolyte  may  be  used  although  new  is 
better.  If  the  old  is  to  be  used  it  should  be 
poured  from  the  jars  into  an  earthenware  or 
glass  vessel  and  allowed  to  settle.  When  replacing  carefully  pour  off  and  use 
the  clear  portion  only. 


Fig.  322. 


Pig.  323. 

Cover  Sealing. — A  number  of  special  types  of  covers  are  in  use.  The  point 
in  the  cover  through  which  the  post  projects  is  the  hardest  part  to  seal.  With 
the    idea    of    making    the    part    leak-proof    the    several    manufacturers 


have 


304 


Automotive  Trade  Training 


developed  special  methods  and  designs  of  manufacture  and  sealing.  Jobs  102, 
109  and  110  give  the  method  of  opening  and  resealing  the  Willard,  Exide,  and 
Cincinnati  types,  since  these  are  fairly  representative  of  all  types. 


*^- 


Fig.  324. 

JOB  102.  OPENING  WILLARD  TYPE  "SJWN"  AND  "SJRN"  BATTERY 

1.     Cut  off  the  terminal  posts  as  illustrated  in  Fig.  325,  using  a  hack  saw. 


This  applies  for  the  clamp  terminal, 
with  a  13/16"  drill. 


If  burned  on  terminals  are  used  drill  off 


Fig.   325. 

2.  To  remove  the  top  connectors,  place  drill  jig  Z72  over  the  top  of  the 
connector  head  drilling  with  the  same  drill  as  for  the  terminals.  Drill  to  a 
depth  just  sufficient  to  remove  the  connector  or  strap  from  the  posts.  Refer 
to  Fig.  326. 


2r7-f. 


Fig.  326. 

3.     Use  a  coarse  file  to  smooth  off  the  post  extensions  left  by  operation  2. 
This  leaves  a  flat  surface  on  the  top  of  the  insert  in  the  special  Willard  cover. 


Batteries  and  Battery  Care 


306 


making  it  easier  to  center  the  drill  for  the  next  operation.     Refer  to  Fig.  327. 
4.     To  release  the  posts  from  the  insert  where  they  are  burned  together 


Pig.   327. 

just  at  the  insert  top,  it  is  necessary  to  use  a  57/64"  drill.  The  Jig  Z94  is  made 
with  a  slight  variation  of  internal  diameters  so  that  one  end  will  fit  over  the 
insert.     For  method  of  use  refer  to  Fig.  328. 


Z^^ 


Fig.   328. 

5.  With  post  builder  Z93  all  connecting  strap  posts  are  built  to  a  height 
of  1  5/16"  above  the  top  of  the  connecting  strap  which  holds  the  group 
together.  After  removing  the  post  builder  the-  top  of"  the  post  is  beveled  to 
permit  of  easy  assembly  of  the  cover.     The  .bevel  is  indicated  at  A,  Fig.  329. 


Z-93 


/ 


Fig.    329. 

6.  The  elements,  having  been  repaired,  may  now  be  replaced  in  the  jars 
so  that  the  positive  terminal  is  to  the  front  when  the  name  plate  end  is  to  the 
right. 

7.  File  and  clean  the  cover  inserts  at  Point  A,  Fig.  330,  to  a  point  3/16" 

A  A 

B\  \  /  ^  B 


Fig, 


above  the  cover.     Be  certain  to  remove  any  roughness  caused  by  the  pliers  at 
point  B  while  handling. 


306 


Automotive  Trade  Training 


8.     Replace  the  covers  so  that  their  top  edges  are  ^"  above  the  top  edge 
of  the  jars,  tapping  lightly  with  the  hammer.     Refer  to  Fig.  331. 

] 


Fig.   331. 

9.  To  weld  or  burn  the  post  and  insert  together  and  form  a  perfect  seal,  the 
burning  form  Z87  is  first  placed  over  the  post  and  insert  and  then  the  flame 
is  applied.     Refer  to  Fig.  332. 

2-87 


Fig.    332. 
10.     Thoroughly  brush  and  clean  the  top  of  the  post  with  a  wire  brush. 
Build  up  a  stub  post  using  burning  form  ZSS  on  positive  posts  and  Z89  on  the 
negative  posts.     Refer  to  Fig.  333. 

1 


B^-T.  88 -Z 

Fig.    333. 
11.     Proceed  with  the  job  finishing  it  up  as  indicated  in  Job  103. 

JOB  103.     REASSEMBLING  THE  BATTERY. 
1.     Having  made  all  repairs  the  elements  may  be  reassembled  in  the  jars 

and  the  covers  sealed  in  place.  In 
order  that  the  covers  may  be 
placed  quickly  and  a  fit  insured 
they  are  taken  one  at  a  time  and 
carefully  fitted  to  the  jar  and  ele- 
ment they  are  to  cover.  Remove 
the  covers  taking  care  to  place 
them  so  that  they  are  not  mixed 
in  replacing.  Next  use  the  gas 
flame  to  warm  the  cover  well  about 
the  post.  This  will  also  insure  the 
parts  being  dry,  which  is  abso- 
lutely essential  to  a  perfect  seal. 
Refer  to  Fig.  334. 


Fig.  334. 


Batteries  and  Battery  Care 


307 


2.  After  warming  the  well  of  the  post  with  the  gas  flame,  pour  in  melted 
sealing  compound  until  the  well  is  nearly  full.  While  still  hot  the  cover  must 
be  pressed  into  position.  This  insures  the  parts  being  sealed  tightly.  The 
method  of  pouring  the  well  is  shown  in  Fig.  335. 


Fig.   335. 

3.     Using   a    gas    flame    as    indicated    in    Fig.    336A,    the    workman    should 
carefully  dry  the  space  between  the  jar  edges  and  the  cover.     With  a  pouring 


Pig  336A. 

dipper,  Fig.  336B,  pour  the  space  between  the  jar  and  cover  about  one-half  full 
of  sealing  compound.  ,  After  this  first  amount  has  had  an  opportunity  to  cool 


Pig.  336B. 


Fig.  336C. 


and  set,  the  space  is  filled  a  little  more  than  full  of  the  sealing  compound.  A 
steady  motion  is  needed  in  pouring  in  order  that  the  job  has  the  appearance 
of  careful  workmanship  when  it  is  finished.     With  a  heated  putty  knife,  Fig. 


308 


Automotive  Trade  Training 


336C,  the  portion  of  the  compound  above  the  cover  and  the  jar  may  be  care- 
fully removed.     The  heat  in  the  blade  will  leave  the  job  smooth. 

4.  If  care  has  been  used  in  removing  the   terminals  and  the   straps,   the 

posts  will  need  but  little  cleaning 
to  permit  the  strap  and  terminals 
to  come  to  their  correct  position 
one-fourth  inch  above  the  cell 
covers.  The  post  and  connector 
may  be  burned  together  in  the 
manner  indicated  in  Fig.  337. 

If  the  post  in  any  case  is  too 
short  to  permit  of  proper  assem- 
bly, it  should  be  lengthened  by 
building  up.  To  do  this  place  a 
post  builder,  which  is  nothing 
more  than  a  piece  of  iron  with  a 
proper  size  hole  in  it,  over  the 
stub,  use  the  lead  burning  flame 
to  melt  the  lead  into  the  mold, 
and  fuse   it   with   the   top 'of  the 

stub  post.     In  this  way  the  post  may  be  built  to  the  desired  height.     After  the 

post  is  right  the  connectors  are  burned  on  in  the  usual  manner.     Refer  to  Fig. 

338. 

Very  frequently  the   clamp  instead  of 

the   burned  type   of   terminal   is   used.     In 

case   of  this   construction   the   old  post  is 

very    frequently    undersize    and    otherwise 

imperfect.     In     such     case     the     old    one 

should  be  removed  and  a  new  one  built  up. 

5.  Fill  the  battery  immediately  it  is 
assembled,  with  specific  gravity  of  the 
proper  density.  This  as  indicated  pre- 
viously will  be  the  same  as  that  removed. 
Where  new  wood  separators  are  used  the 
electrolyte  may  be  25  to  50  points  higher. 
Be  certain  to  have  plenty  of  solution  above  the  plates  but  do  not  fill  too  full. 
A  sectional  cut  of  a  battery  shown  in  Fig.  339  will  show  the  proper  level. 


Fig.    337. 


90  2-91 


Fig.    338. 


Fig.   339. 


Batteries  and  Battery  Care 


309 


JOB  104.     ELEMENT  REPAIR  AND  INSPECTION. 

1.     With  the  battery  open  the   separators  are   removed   from  the  element 
in   order  to  permit   of  plate   inspection.     If   the   cover   has   been   removed   the 

positive  and  negative  groups  are  also  separated. 
The  method  of  doing  this  is  illustrated  in  Fig.  340. 
Fig.  341  shows  the  method  of  removing  the 
separators  in  this  case,  after  the  groups  have  been 
pulled  apart. 

2.  Inspect  all  plates  as  suggested  in  forepart 
of  the  chapter.  Also  inspect  separators,  cells  and 
case.    ■ 

3.  In  case  one  or  two  plates  of  a  group  are 
bad  ~v(^hile  the  others  are  judged  fit  for  further  ser- 
vice the  bad  ones  should  be  removed.  To  do  this, 
use  a  hack  saw  making  a  cut  through  the  strap  on 

tach  side  of  the  defective  plate.  Place  the  new  plate  in  position,  having  all  of 
the  group  assembled  dn  the  burning  rack.  With  the  lead  burning  flame  burn 
the  parts  together. 

4.  A   very   frequent    cause    of   trouble    with   a       

single  cell  is  a  bad  insulator,  which  permits  of  a 
short  circuit. 

5.  Another  cause  is   defective   burning  in 


Fig.    3^0. 


It 
trouble 


may   be   of   a   nature    hard   to   locate    until 
develops  in  service. 

P>.  When  part  of  a  group  of  plates  is  worn  out 
in  normal  service  it  is  not  as  a  rule  advisable  to 
rjeplace  them  with  new  ones.  Rather  the  entire 
group  should  be  replaced.  If  it  is  a  case  of  all 
groups  being  practically  worn  out  the  battery 
should  not  be  rebuilt  but  replaced  with  another. 

;.  W^hen  the  groups  are  in  good  condition  they  are  cleaned  and  reas- 
sembled ready  for  the  separators.  Fig.  343  shows  the  method  of  placing  the 
positive  and  negative  groups  together. 


Fig.    341. 


Fig.    342. 


Fig.    343. 


8.  Fig.  343  shows  the  element  complete  except  for  the  separators.  The 
negative  group  always  has  one  more  plate  than  the  positive.  This  permits  of 
the  negative  plates  forming  the  outside  plate  in  every  case. 

9.  Fig.  344  shows  the  method  of  placing  separators  in  the  element.  One 
separator  is  placed  between  each  two  plates.  The  ribs  on  the  wood  separator 
always  go  next  to  the  positive  plates.  In  cases  where  other  forms  of 
separators  are  used  the  same  principle  holds.  They  should  be  assembled  to 
allow  as  much  of  the  positive  plate  surface  free  as  is  possible.     The  repairman 


310 


Automotive  Trade  Training 


Fig.    344. 


should  .make ,  certain  that  the  separators  project 
slightly  on  the  sides  and  top.  Since  the  element 
rests  on  the  cell  ribs  the  bottom  is  left  flush. 

10.  Fig.  345  shows  the  element  complete  ready 
for  placing  in  the  jar. 

11.  In  placing  the  element  in  the  jar  use  rea- 
sonable care  that  it  does  not  bind  at  any  point  in 
such  manner  that  the  jar  is  likely  to  be  broken. 
Fig.  346  shows  a  jar  broken  as  the  result  of  care- 
less handling.  A  battery  will  not  stand  being 
dropped  from  any  height  onto  a  hard  surface.  To 
drop  it  an  inch  may  result  in  broken  jars. 


Fig.   345. 


Fig.    346. 


12.  To  remove  a  broken  jar  it  is  necessary  to  heat  it  with  hot  water  or 
steam  for  at. least  five  minutes.  It  may  be  poured  full  of  boiling  water,  after 
which  it  should  be  removed  by  pulling  up  on  it  with 

two  pairs  of  pliers  as  shown  in  Fig.  347, 

13.  Before  replacing  the  new  jar  it  is  well  to 
heat  it  in  the  same  manner  as  the  old  one.  In  the 
meantime  remove  any  sealing  compound  which 
might  obstruct  the  placing  of  the  new  jar.  When 
the  jar  is  in  position  it  is  sealed  in  the  same  manner 
as  the  old  one.  This  varies  somewhat  for  different 
batteries.  In  some  cases  the  jars  are  not  sealed  at 
all,  in  others  they  are  sealed  at  the  top  edge,  and  in 
still  others  they  are  sealed  all  around. 

14.  The   use   of  hot   water  to   soften   all   hard 

rubber  parts  is  recommended  to  the  student  mechanic.  This  leaves  the  covers 
and  jars  in  a  semi-pliable  state  with  the  result  that  there  is  less  likelihood  of 
their  being  broken  as  they  are  handled. 

15.  The  three  most  common  methods  of  grouping  cells  in  the  battery 
boxes  are  shown  in  Fig.  348. 


Fig.    347. 


JOB  105.     BATTERY  SHOP  REPAIR  METHODS. 

General  Test  to  Determine  the  Condition  of  the   Storage   Battery. — The 

first  test  to  be  applied  to  the  battery  when  it  comes  to  the  repair  shop  for 
charging  or  repair  is  one  to  determine  the  voltage  on  open  circuit.  This  should 
be  six  volts  or  a  little  higher  for  a  three  cell  battery,  correspondingly  more  for 
ether  types.  An  instrument  similar  to  the  Weston  Model  441  Faultfinder 
should  be  used  for  this  test  using  the  30  volt  range.  Having  made  the  test  on 
open  circuit,  i.  e.,  without  the  battery  discharging,  a  resistor  for  making  a 
discharge  test  reading  on  the  voltmeter  is  then  connected  across  the  battery 
terminals. 


Batteries  and  Battery  Care 


311 


The  resistor  is  made  from  nine  feet  of  No.  16  soft  iron  wire.     The  inherent 
resistance   of  the  iron   will  prevent  more   than  a  certain  amount  of  current 


I'l : — II 

f 

J 

@ 

@          1 

1     <==r-^      1 

6  volt  (3  cell) 

battery. 

assembly  I 


@    @   C:^   @  CI 

b(0)@ 

1  , 

SI 

1 L 

■4 

1 H 1 

6  volt  (3  cell) 

battery 

assembly  2 


dBldSl 


.qpl 


Fig.   348. 


M 


12  volt  (6  cell) 

battery 

assembly  1 


flowing.  Connect  the  resistor  and  instrument  as  shown  in  Fig.  349.  If  the 
voltmeter  is  now  below  five  volts  the  battery  is  either  discharged  or  in  poor 
physical  condition. 

Allowing  the  resistor  to  remain  as  before,  the  instrument  is  connected  to 
make  a  reading  on  the  three  volt  range  while  testing  the  individual  cells.     If 


a/rrrer 


Fig.   349. 


312 


Automotive  Trade  Training 


Fig.    350. 

all  are  about  equal,  the  battery  is  likely  discharged.     If  one  or  more  of  the  cells 
give  readings  exceptionally  low  it  is  possible  that  these  have  defective  plates. 

Next  make  a  test  for  the  specific  gravity  of  the  several  cells.  If  the  gravity 
readings  are  low  in  all  cases  this  indicates  that  the  battery  is  exhausted  from 
continued  discharge.  Charge  the  battery  and  then  make  the  same  test  as  just 
indicated.  If  there  are  no  defects  in  the  cells  the  voltage  registered  with  the 
resistor  in  place  and  current  flowmg  will  be  about  two  volts  per  cell.  If, 
however,  the  voltage  drops  considerably  the  plates  are  likely  defective  in  the 
cell  showing  the  drop. 

JOB  106.     MAKING  AND  USING  A  TEST  OUTFIT  FOR  READING 
VOLTAGE  OF  INDIVIDUAL  CELLS  WITH  CLOSED  CIRCUIT. 

First  secure  two  fiive-inch  spike  nails.  Grind  the  ends  of  these  to  a  sharp 
point.  Next  take  a  blo^k  of  fiber  or  hard  wood  four  inches  long  and  approxi- 
mately one  inch  square  as  a  support  for  the  spikes 
Drill  holes  through  the  wood  block  one-half  inch 
from  each  end  m  which  mount  the  spikes.  To  secure 
them  in  position  use  the  hand  drill  to  drill  a  #2"  hole 
through  them  as  they  are  in  position.  Place  a  rivet 
pm  or  cotterkey  through  the  holes  to  lock  the  parts 
together  In  the  center  mount  a  file  handle  to  serve 
as  a  handle  for  the  instrument  Refer  to  Fig.  351. 
Some  form  of  terminal  must  be  mounted  on  the 
spike  heads  to  which  the  terminals  from  the  instru- 
ment (voltmeter)  may  be  readily  attached. 

The  resistor  is  made  from  one  foot  of  Nichrome 
resistance  wire  one-eighth  inch  in  diameter.  The 
ends  of  the  wire  are  soldered  to  the  spikes.  When 
the  spikes  are  firmly  pressed  into  the  cell  terminals 
approximately  50  amperes  will  flow  across  them 
through  the  resistor.  The  voltage  reading  should  be 
made  at  the  time  the  current  is  flowing  If  the 
voltage  does  not  read  1,6  or  more  with  this  dis- 
charge, the  plates  are  not  in  healthy  condition.  The 
cells  failing  must  be  repaired. 


/~N 


Fig.  3r.i 


Batteries  and  Battery  Carh  313 

JOB  107.     CADMIUM  TEST. 

The  purpose  of  the  cadmium  test  is  to  determine  which  group  of  the  plates 
in  a  cell  which  is  known  to  be  bad  is  at  fault.  Since  the  fact  remains  that  if 
one  group  is  at  fault  the  battery  must  be  opened,  little  value  can  be  attributed 
to  the  test.  Unless  the  operator  is  one  well  versed  in  the  theory  and  action 
of  the  storage  battery  the  test  may  be  very  misleading.  For  the  expert  battery 
repair  man  the  test  may  be  of  value  in  showing  which  group  contains  the 
defective  plates  and  in  that  way  save  some  time  in  making  the  repairs. 

For  those  who  desire  to  undertake  the  test  the  following  instructions  may 
be  a  guide: 

Have   the   battery  in   fully   charged   condition. 

The  lead  attached  to  the  spike  havmg  the  cadmium  stick  should  be  connected 
to  the  voltmeter  terminal  marked  three  volts.  Connect  the  lead  attached  to 
the  other  spike  to  the  terminal  of  the  voltmeter.  Insert  the  cadmmm  stick  into 
the  vent  hole  of  the  cell  under  test,  Fig.  352,  taking  care  that  it  does  not  come 


Fig    352. 

in  contact  with  the  plates.  Press  the  other  spike  into  the  positive  terminal 
of  the  cell  and  with  the  finishing  rate  of  charging  current  passing  into  the  cell 
observe  the  reading  of  the  voltmeter.  The  cadmium  stick  should  be  kept  in  the 
electrolyte  sufficiently  long  before  taking  the  reading  until  the  voltage  does 
not  show  any  changing.  If  the  positive  plates  are  in  good  condition  the  reading 
will  be  between  2.35  and  2.45  volts. 

If  the  reading  is  less  than  2.35  volts  it  is  probable  that  the  positive  plates 
arc  defective. 

Transfer  the  spike  from  the  positive  terminal  to  the  negative  terminal. 
The  reading  this  time  will  be  to  the  left  of  zero  for  a  fully  charged  negative  in 
good  condition  and  should  be  between  0.1  and  0.2  volt.  If  the  reading 
jipproaches  zero,  or  if  it  is  to  the  right  of  zero,  the  negative  plates  are  probably 
defective. 

If  the  test  on  both  the  positive  and  negative  give  readings  which  approach 
zero,  the  battery  is  short  circuited. 

In  general  it  is  understood  in  the  case  of  a  battery  on  charge  that  if  the 
cadmium  test  to  the  negative  plates  does  not  give  a  minus  reading  the  battery 
is  not  up  to  capacity,  but  on  the  other  hand,  a  minus  reading  is  not  proof  that 
the  battery  is  up  to  full  capacity.  This  can  be  determined  by  making  a 
discharge  test. 

The  battery  should  be  discharged  at  its  normal  discharge  rate  until  the 
voltage  per  cell  is  1.8  volts  with  current  flowing.  Keep  a  record  of  the  time  in 
hours  required  to  do  this.  Then  with  a  discharge  current  of  five  amperes 
flowing  the  cadmium  tests  should  be  repeated. 

The  reading  of  the  positive  plates  should  be  about  2.05  volts  and  the 
negative  plates  should  show  0.25  volt  to  the  right  or  plus. 

If  the  reading  to  the  positive  group  is  much  below  two  volts,  it  is  certain 


314  Automotive  Trade  Training 

that  the  positive  group  is  defective.  If  the  reading  to  the  negative  plates  is 
greater  than  0.25  plus,  it  is  probable  the  negative  group  is  defective. 

When  the  readings  indicate  defective  plates,  it  is  best  to  open  the  cells  and 
make  a  further  inspection  of  the  plates. 

Upon  reaching  the  voltage  of  1.8  volt  per  cell  the  battery  should  have 
given  its  rated  ampere  hour  capacity.  This  is  determined  by  multiplying  the 
ampere  discharge  rate  by  the  length  of  time  rated  in  hours,  w^hich  has  been 
necessary  to  discharge  the  battery  to  that  point.  If  the  full  capacity  of  the 
battery  has  not  been  given  it  is  probable  that  the  plates  are  defective,  and  the 
cells  should  be  opened  up  and  the  plates  given  further  inspection. 

When  the  cadmium  tests  show  the  plates  to  be  in  fully  charged  condition, 
the  gravity  of  the  electrolyte  should  be  determined.  This  should  be  between 
1.275  and  1.300.  If  it  is  not,  it  should  be  corrected  until  it  does  show  the  proper 
density. 

If  the  density  indicates  a  fully  charged  cell,  but  the  cadmium  readings  do 
not  show  fully  charged  plates,  the  charge  should  be  continued  to  see  if  the 
cadmium  readings  will  not  become  what  they  ought  to  be.  If  not,  the  plates 
are  probably  defective.  The  battery  should  be  opened  up  and  receive  the 
necessary  repairs. ' 

JOB  108.     GROUNDED  BATTERY. 

As  mentioned  previously,  the  grounded  battery  is  usually  due  to  spilled 
electrolyte.  This  electrolyte,  coming  in  contact  with  the  metal  box  or  battery 
container,  will  produce  a  circuit  between  the  container  and  one  or  more  of  the 
battery  terminals.  If  the  system  used  is  the  single  wire  or  grounded  return 
this  new  circuit  will  cause  a  short  circuit  on  the  battery.  For  a  short  circuit 
to  develop  on  the  two-wire  system  both  the  positive  and  negative  terminals 
must  be  grounded  simultaneously. 

To  test  the  grounded  return  system,  first  remove  the  ground  connection. 
Connect  the  30  volt  range  of  the  Fault  Finder  between  this  terminal  and  the 
frame  of  the  car.  Any  indication  on  the  instrument  will  be  due  to  a  short 
circuit  to  the  car  frame  from  the  other  battery  terminal. 

In  the  two-wire  system  each  battery  terminal  should  be  tested  for  ground 
to  the  car  frame. 

In  all  cases  it  is  very  important  to  remove  all  moisture  from  the  top  of  the 
battery.  This  will  often  remove  the  cause  of  the  ground.  In  some  instances 
the  battery  case  is  so  saturated  with  the  electrolyte  that  it  is  hard  to  remove 
the  cause  of  the  short  circuit.  Cracked  cells  may  be  the  cause  of  short 
circuits. 

JOB  109.     REMOVING  AND  RESEALING  EXIDE  SINGLE  COVER 

TYPE  COVERS. 

1.  Remove  the  lead  straps.  These  may  be  bored  with  a  five-eighths  inch 
wood  bit  as  indicated  in  Fig.  353.  Just  under  the  lead  straps  the  special  form 
of  lock  nut  is  visible.  These  nuts  are  used  to  seal  the  joint  where  the  post 
comes  through  the  cover.  The  section  of  an  Exide  battery,  as  shown  in  Fig. 
354,  indicates  the  secure  manner  in  which  the  parts  are  locked  together.  Tke 
sealing  compound  locking  the  elements  in  the  jars  may  be  softened  by  one  of 
the  methods  indicated  in  Job  101,  after  which  the  elements  may  be  removed 
from  the  cells. 

2.  To  remove  the  sealing  nuts  the  special  wrench  shown  in  Fig.  357  should 
be  used. 

3.  After  repairs  are  made  to  the  element  it  is  assembled  in  the  cover  and 
the  sealing  nuts  are  tightened  part  way,  using  only  the  fingers  for  this  work. 


Batteries  and  Battery  Care 


315 


Fig.  353.     Boring  Connector. 

Be  very  certain  to  have  the  soft  rubber  washers  in  place  in  order  to  make  a 
tight  joint  and  protect  the  cover.  With  the  groups  on  edge,  as  indicated  in 
Fig.  355,  the  separators  are  inserted  making  certain  that  the  flat  side  of  the 
wood  is  against  the  negative  plates. 


Section  of  Battery — Burned  Connections,  Single  Plan&e  Cover 
Fig.    354. 


316 


Automotive  Trade  Training 


4.  With  the  separators  all  in  place  and  projecting  equally  on  each  side  the 
sealing  nuts  are  locked  tight  using  the  special  wrench. 

5.  The  sealing  nut  should  be  locked  in  position  as  indicated  in  Fig.  356. 


Pig.  357.     Sealing   Nut   Wrench. 

Fig.  355.     Inserting  Separators. 
A  center  punch  or  nail  may  be  used  to  punch  several  points  to  prevent  the  nut 
working  loose. 


J^^UM 

e.s.B.co.izzs 

Fig.   356.    Locking   Sealing   Nut. 

JOB  110.     OPENING  CINCINNATI  BATTERIES. 

Fig.  359  shows  the  patented  feature  of  the  Cincinnati  storage  battery  cover 
hacking  device.     On  the  group  post,  just  above  the  point  where  the  cover  fits, 


Batteries  and  Battery  Care 


317 


Fig.  358.     Cincinnati  Storage  Battery. 


is  a  threaded  portion.  Projecting 
above  this  threaded  portion  is  a 
round  smooth  post.  The  nut 
which  is  used  to  lock  the  cover  to 
the  group  has  a  nipple-like  ar- 
rangement on  its  top  which  fits 
over  the  smooth  part  of  the  post 
when  the  threaded  portion  of  the 
nut  locks  over  the  threaded  por- 
tion of  the  post.  To  dismantle, 
proceed  as  follow: 

1.  Centerpunch  the  centers  of 
the  connecting  straps  and  termi- 
nals over  the  post. 

2.  Drill  with  a  ^"  drill  to  a 
depth  of  one-fourth  inch  and  re- 
move the  straps  and  terminals. 

3.  Inspect  the  post  tops  to 
learn  if  the  line  of  separation  be- 
tween the  inner  post  and  the  nu( 
is  evident.  If  not  apparent  it  is 
useless  to  attempt  to  turn  off  the 
nut.  Use  a  file  to  file  off  the  top  of  the  post  and  nut  until  the  line  or  circle 
between  the  two  appears. 

4.  Place  a  socket  wrench  over  the  hexagonal  portion  of  the  nut  and  turn 
or  back  it  off  the  post. 

5.  After  loosening  the  nut  it  may  be  desirable  to  turn  it  back  in  position 

until  the  covers  are  loosened 
in  the  usual  manner  by 
steaming,  hot  water,  or  gas 
flame. 

6.  When  the  element  is 
finally  removed  the  cover  is 
quickly  removed  by  releasing 
the  nuts.  In  reassembling  be 
certain  to  use  the  soft  rubber 
washers   under   the   nuts. 

7.  After  repairs  have 
been  made  to  the  element,  it 
is  assembled  in  the  cell  jar 
and  the  cover  placed  in  posi- 
tion, where  it  is  locked  under 
the  nuts,  and  the  outer  edges 
of  it  are  sealed  to  the  jar. 

8.  In  burning  the  con- 
necting  straps    and    terminal 


Sleeve  And  Post  Fuses  TOGETMni ) 


Fig.  359. 


Cincinnati  Storage  Battery-  Cover  Locking 
Device. 


posts  in  position  the  upper  edge  of  the  nut  will  again  be  burned  to  the  inside 
post.     This  insures  the  nut  remaining  permanently  in  position. 

JOB  111.     MAKING  AND  USING  ELECTROLYTE. 


Electrolyte,  as  explained  previously,  is  made  by  adding  sulphuric  acid  to 
distilled  water.  The  water  should  never  be  added  to  the  acid,  but  in  mixing 
the  acid  is  always  added  to  the  water.  If  the  operation  is  reversed  the  water 
striking  the  acid  is  very  likely  to  cause  such  violent  action  as  to  throw  the 


318  Automotive  Trade  Training 

solution  from  the  receptacle  in  which  it  is  being  mixed.     The  amount  of  acid 
added  to  the  water  determines  its  specific  gravity. 

Making  Electrolyte. — In  making  up  the  electrolyte,  glass  jars  or  earthen 
jars  should  be  used.  Metal  containers  outside  of  burned  lead  vessels  may  not 
be  used.  It  is  well  also  to  have  a  glass  funnel  and  syringe  available.  The 
syringe  may  be  an  old  hydrometer  case  with  the  hydrometer  removed. 

-.  When  mixing  the  acid  and  water  they  are  figured  not  by  weight,  but  by 
volume.  For  electrolyte  of  varying  specific  gravity  consult  the  following  table. 
The  student  will  remember  the  specific  gravity  of  water  as  1.000,  and  of  pure 
sulphuric  acid  as  1.835.  In  purchasing  the  acid  it  must  be  ordered  from  the 
chemical  company  or  supply  house  as  C.  P.,  H.,SO^,  which  is  chemically  pure 
sulphuric  acid.     The  distilled  water  may  be  secured  from  the  same  source. 

1.150  Sp.  Gr.  equals  one  part  sulphuric  acid  to  6     parts  distilled  water. 

1.200  Sp.  Gr.  equals  one  part  sulphuric  acid  to  4     parts  distilled  water. 

1  250  Sp.  Gr.  equals  one  part  sulphuric  acid  to  3     parts  distilled  water. 

1.285  Sp.  Gr.  equals  one  part  sulphuric  acid  to  2  5  parts  distilled  water. 

1.325  Sp.  Gr.  equals  one  part  sulphuric  acid  to  2     parts  distilled  water. 

Allow  the  electrolyte  to  cool  below  90  degrees  F.  before  putting  it  into  the 
cells  of  the  battery. 

Filling  the  Battery  with  Electrolyte. — All  cells  should  be  filled  with 
electrolyte  up  to  one-half  inch  over  the  top  of  the  plates.  If  the  elements  have 
been  out  of  the  jars  long  enough  to  allow  the  plates  to  dry  out,  the  battery 
must  be  left  tor  at  least  eight  hours  after  filling  before  placing  on  charge. 

Determining  Strength  of  Electrolyte  to  Use  in  a  Repaired  Battery. — If  the 
plates  are  new  the  electrolyte  used  for  filling  should  have  a  specific  gravity  of 
1.325;  if  they  are  old  plates  badly  sulphated,  the  electrolyte  should  be  1.150 
specific  gravity,  while  if  old  plates,  and  any  doubt  about  their  condition  is  held 
by  the  workman,  the  electrolyte  used  should  be  1.200.  To  the  student  it  is  now 
apparent  that  if  the  specific  gravity  of  the  electrolyte  drawn  ofif  were  known  it 
would  be  easier  to  know  just  what  specific  gravity  to  fill  the  repaired  battery 
with.  All  acid  which  may  be  in  the  plates  will  be  foi-ced  out  when  the  battery 
is  charged  and  will  increase  the  strength  br  density  of  the  electrolyte.  This  is 
true  of  all  old  plates,  but  in  the  case  of  new  plates  the  gravity  drops  slightly 
since  some  acid  is  always  retained  in  the  plates.  This  is  the  reason  for  using 
the  1.325  electrolyte  when  filling  over  new  plates. 

Adjusting  Electrolyte. — A  fully  chargecj  battery  should  show  a  specific 
gravity  of  1.280  to  1.300.  If,  after  the  cells  are  fully -charged,  the  electrolyte 
is  not  of  the  proper  density,  the  proper  correction  must  be  made.  If  too  high, 
the  cell  must  have  a  portion  of  its  electrolyte  drawn  off  with  the  syringe  and  a 
like  amount  of  distilled  water  added.  If  too  low,  a  quantity  ot  the  electrolyte 
is  drawn  ofi  and  electrolyte  of  1.400  specific  gravity  is  added  After  the  change 
is  made  the  charge  must  be  continued  for  a  time  and  then  final  tests  and  adjust- 
ments made. 

JOB  112      CHARGING  A  REPAIRED  BATTERY. 

The  battery  should  be  placed  on  charge  at  a  low  rate,  approximately  that 
of  the  finish  rate  stamped  on  the  name  plate.  It  may  be  continued  on  charge 
until  there  is  no  further  rise  in  gravity  in  any  of  the  cells.  A  reliable  thermom- 
eter must  be  used  to  check  up  the  temperature.  It  at  any  time  the  battery 
heats  to  110  degrees  F.,  the  current  must  be  reduced  until  the  temperature  is 
below  90  degrees.  When  no  further  rise  is  noticeable  in  the  gravity  readings 
for  two  to  five  hours,  the  gravity  must  be  adjusted  to  read  between  1.280  and 
1.300. 

Acid  must  never  be  added  to  bring  up  the  gravity  of  a  cell  unless  it  shows 
no  rise  whatever  over  a  period  of  from  two  to  five  hours.    The  cadmium  test 


Batteries  and  Battery  Care 


319 


is  sometimes  used  to  determine  if  the  plates  are  fully  charged.  If  a  part  of  the 
cells  are  fully  charged  while  others  do  not  show  a  full  charge,  the  low  ones 
should  be  charged  individually  in  an  attempt  to  bring  them  to  the  proper 
gravity  reading.  It  is  only  when  this  has  failed  to  bring  the  cell  above  the 
fixed  point  after  several  hours  of  charging  that  the  repairman  may  feel  free  to 
make  adjustment  of  the  acid.  It  must  be  definitely  understood  that  batteries 
cannot  be  recharged  by  adding  acid.  Acid  is  added  to  the  electrolyte  only 
after  all  is  driven  from  the  plates  by  charging  and  then  only  to  insure  having 
the  proper  amount  in  the  cell,  that  its  future  action  may  be  correct  as  fixed  by 
the  generally  accepted  standards. 

CHARGING  BATTERIES  AND  BATTERY  CHARGING  EQUIPMENT. 

The  prime  requisite- in  charging  batteries  is  a  D.  C.  current.  A.  C.  current, 
as  explamed  m  Chapter  11,  may  not  be  used  for  this  work.  Other  essentials 
are  methods  of  controlling  the  voltage  and  the  amperage  and  instruments  to 
measure  the  voltage  and  amperage.  There  are  many  devices  and  methods  in 
use  for  the  work  of  battery  charging.  Some  are  simple  and  inexpensive. 
Others  are  very  elaborate  and  quite  expensive.  The  number  of  batteries  to 
be  cared  for  and  the  type  of  current  or  power  available  are  determining  factors 
in  deciding  on  equipment  as  well  as  method.  Where  110  volt  D.  C.  lighting 
current  is  available  it  is  comparatively  simple  to  use  it.  Where  it  is  desired  to 
use  the  A.  C.  current  some  form  of  transformer  or  rectifier  must  be  used. 

Charging  a  Battery  from  a  110  Volt  Lighting  Circuit. — It  is  possible  tc 
charge  from  one  to  fifteen  6-volt  batteries  by  this  metbod.  By  "referring  to 
Fig.  360  the  student  will  learn  the  method  of  wiring  for  a  single  battery.     The 


/ 


T> 


flO  VOLT/OO  yVATT  l.^MP3 
^^2  o.p  carbon  /<smpsj 


Pf    @ 


y 


y  ©  p 


p 


Fig.  360. 

outfit  consists  of  a  board  or  slate  panel,  on  which  is  mounted  a  two-pole  throw- 
out  switch  for  turning  on  and  off  the  110  volt  current.  This  line  must  be 
protected  with  15  ampere  fuses.  It  is  necessary  to  determine  which  line  is 
negative  and  which  positive.  This  may  be  determined  by  tht  use  of  a  volt- 
meter, or  by  placing  a  teaspoonful  of  salt  in  a  tumbler  of  water  and  dipping 


320 


Automotive  Trade  Training 


the  two  leads  from  the  110  volt  circuit  in  the  tumbler.  This  will  indicate 
polarity  since  the  small  gas  bubbles  forming  on  the  one  wire  show  it  to  be  the 
negative  lead.     The  insulation  must  be  removed  from  the  ends  of  the  leads. 

25  QrT7p  Cotnhined  SrriUh  and 
^^  Plug  Coi-ool.  (20  Amp  Tuseis) 


(NB2J) 


D  T.  Cvlooi  (20  "Amp  Fvses) 

Conneciioos  For  Chot^xog  fioiierie^ 
Fig.  361. 


Having  determined  the  polarity,  the  mounting  may  be  made  permanent  on 
the  panel  and  the  positive  marked  with  a  plus  sign  while  the  negative  is  marked 
with  a  negative  or  mmus  sign. 

Next  mount  six  porcelain  lamp  sockets  on  the  panel,  wiring  them  so  that 
the  current  must  flow  through  them  to  get  to  the  positive  terminal  to  which 
the  battery  will  be  connected.  The  positive  terminal  of  the  battery  is  always 
connected  to  the  positive   charging  lead.     The   negative   lead   is   run  to   the 


^2*  ^ 


//O/o//  jQfivc/  Currcn/  C/ixwf 


D    D 


— — h 


'o^  Cuf  Oui(lAmp.rajx\st 


cTo.o  _r 0*00  _J~ cTo o  _r  o*o_9_  J~ "oo_o 


O'OO^J"  0"0JD 


Fig.  362. 

negative  battery  terminal  direct  unless  the  amperage  flowing  is  desired  to 
show  on  an  ammeter  when  the  battery  is  charging.  In  this  case  the  ammeter 
is  placed  in  series  on  the  negative  line. 

Into  each  of  the  lamp  sockets  is  screwed  a  32  C.  P.  carbon  bulb.  The 
amount  of  current  permitted  to  flow  through  one  bulb  is  1  ampere;  through 
two  bulbs,  two  amperes,  and  through  six  bulbs,  six  amperes.     Consequently 


Batteries  and  Battery  Care  3^3, 

as  many  amperes  will  flow  to  the  battery  as  there  are  bulbs  in  circuit.  To 
take  a  bulb  out  of  circuit  it  is  only  necessary  to  back  it  out  of  the  socket  until 
it  goes  out.  The  current  then  is  reduced  one  ampere.  Manipulating  the  six 
bulbs  will  give  a  charging  range  of  from  one  to  six  amperes. 

Charging  a  Number  of  Batteries  from  110  D.  C.  Circuit.-=^With  the  panel 
shown  in  Fig.  361  a  number  of  batteries  may  be  charged.  The  principle  is  the 
same  as  that  given  above.  Thirty  bulbs  are  arranged  on  the  panel  so  that  a 
charging  rate  varying  from  one  to  thirty  amperes  is  available  by  manipulating 
the  switches  in  addition  to  the  bulbs.  In  making  up  this  panel  slate  is  to  be 
preferred  to  wood  although  the  latter  may  be  used  providing  it  does  not 
interfere  with  the  national  underwriters'  rules.  It  is  best  to  have  an  ammeter 
in  the  negative  line  to  show  the  amperage  flowing. 

In  operation  the  amperage  required  will  be  the  same  as  for  individual 
batteries.  Whatever  flows  through  one  cell  will  flow  through  each  cell.  The 
charging  rate  should  not  exceed  the  lowest  maximum  given  for  any  individual 
battery.  When  the  batteries  are  connected  to  the  charging  leads,  the  positive 
of  the  first  battery  is  connected  to  the  positive  lead,  the  negative  of  the  first 
battery  is  connected  to  the  positive  of  the  next  one,  and  so  on  until  the  number 
desired  are  connected. 

By  manipulating  the  switches  the  correct  charging  rate  may  be  obtained. 
Whatever  amperage  shows  on  the  ammeter  flows  through  each  cell.  To  hold 
this  at  the  desired  point  bulbs  must  be  added  or  withdrawn,  more  bulbs  for  a 
^"'^higher  rate,  fewer  bulbs  for  a  lower  rate. 

TRICKLE  CHARGE  FOR  BATTERIES  IN  STORAGE. 

In  wet  storage  of  batteries  it  is  sometimes  desirable  to  have  a  very  light 
current  of  electricity  pass  through  the  cells  at  all  times  so  as  to  keep  them  in 
good  condition.  Fig.  362  shows  one  method  of  doing  this  where  110  D.  C. 
current  is  available.  Ten  or  more  batteries  are  connected  in  series  and  only 
one  bulb  placed  in  the  line.  The  current  flowing  is  not  sufficient  to  cause  the 
cells  to  gas,  but  is  sufficient  to  keep  them  charged.  Before  going  into  wet 
storage  on  a  trickle  charge,  all  cells  should  be  fully  charged. 

MOTOR  GENERATOR  CHARGING  EQUIPMENT. 

Where  A.  C.  current  is  available  the  equipment  used  for  charging  is 
frequently  a  D.  C.  generator  driven  by  the  A.  C.  motor  which  is  frequently 
direct-connected.  This  equipment  comes  in  sizes  suited  to  all  types  of  repair 
stations.  For  the  owner  or  the  repair  shop  charging  only  a  few  batteries  at  a 
time  the  problem  is  sometimes  solved  by  using  a  generator  from  an  old  car, 
driving  it  by  means  of  a  one-half  H.  P.  motor. 

Charging  Batteries  from  a  220  Volt  Circuit. — It  is  possible  to  use  a  220  or 
higher  voltage  circuit  if  the  bulbs  are  connected  two  in  series,  or  such  suitable 
arrangement  is  made  as  will  care  for  the  higher  voltage. 

Charging  from  D.  C.  Using  a  Rheostat  for"  Resistance  and  Current  Regula- 
tion.— In  cases  where  D.  C.  current  is  available  for  charging  in  a  battery  repair 
shop  where  much  charging  is  done,  the  lamp  bank  on  the  panel  is  not  used  as 
frequently  as  some  form  of  rheostat.  These  may  be  made  up  by  an  experienced 
electrician,  or  purchased  from  supply  houses.  When  so  purchased  the  rheostat 
is  only  part  of  the  charging  set  which  usually  includes  instruments,  switches, 
etc. 

Charging  from  A.  C.  Circuit  using  a  Rectifier. — Numerous  devices  are  on 
the  market  utilizing  A.  C.  current  for  the  source  of  a  charging  current.  In 
every  case  the  A.  C.  current  is  changed  to  D.  'C.  current' before  being  sent  to 


333 


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Batteries  and  Battery  Care  323 

the  charging  circuit.  The  mercury  vapor  bulb  or  similar  lighting  bulb 
equipment  is  frequently  the  heart  of  the  rectifying  instrument.  In  other 
instances  the  rectifier  is  a  rotary  machine,  and  in  still  others  a  vibrating 
machine.  In  every  case  the  A.  C.  current  which  pulsates  through  the  supply 
circuit  in  an  alternating  manner  is  so  converted  or  rectified  that  the  pulsations 
in  the  charging  circuit  all  flow  in  one  direction. 

Tungar  Rectifier. — This  is  made  by  the  General  Electric  Co.,  and  may  be 
had  in  sizes  suitable  for  charging  batteries  from  the  110  A.  C.  lighting  circuit. 
Any  number  of  batteries  from  one^^to  ten  may  be  charged.  Fig.  363  shows  a 
photo  of  this  equipment  which  is  very  satisfactory. 

JOB  113.     CARING  FOR  BATTERIES  ON  CHARGE. 

The  equipment  needed  for  this  work  consists  of  a  hydrometer,  a  syringe, 
a  thermometer,  and  a  test  instrument  similar  to  the  Weston  Fault  Finder  441. 
Proceed  as  indicated  below: 

1.  Take  a  hydrometer  reading  for  each  cell.  Record  same  for  future 
reference. 

2.  Take  voltage  reading  of  each  cell  as  indicated  in  Jobs  106  and  107. 
Record  the  findings. 

3.  If  the  customer's  report  on  battery  and  the  findings  from  the  voltage 
tests  and  hydrometer  readings  warrant,  the  battery  should  be  put  on  charge  at 
the  start  rate  stamped  on  the  name  plate.  It  is  far  better  to  charge  at 
a  low  rate  for  a  longer  time  than  to  attempt  to  hurry  the  job  .at  a  high  rate. 

4.  If  the  battery  is  a  badly  sulphated  one,  or  one  just  rebuilt,  it  is  better 
to  put  it  on  at  the  finish  rate. 

5.  As  the  battery  takes  the  charge  it  will  gas  slightly  at  first,  and  then  as 
the  charge  nears  completion,  more  and  more  freely,  unless  the  charge  rate  is 
reduced  from  the  start  to  the  finish  rate. 

6.  As  the  charge  proceeds  it  is  necessary  to  note  the  temperature  of  the 
electrolyte  within  the  cells.  If  any  oi)e  shows  a  rise  above  110  degrees  F.  the 
charging  rate  must  be  reduced,  or  the  battery  taken  off  the  line  until  it  has 
cooled  below  90  degrees. 

7.  In  making  tests  with  the  hydrometer,  the  fact  that  electrolyte  is  lighter 
at  temperatures  higher  than  70  must  be  considered.  It  is  necessary  to  correct 
the  hydrometer  reading  one  point  for  each  three  degrees  rise  of  the  tempera- 
ture of  the  electrolyte.  For  instance,  if  the  temperature  rises  to  100  degreeis: 
the  correction  would  be  ten  points,  due  to  the  30  degrees  rise.  If  the 
hydrometer  shows  a  reading  of  1.280,  same  should  be  corrected  to  read  1.290. 
This  is  very  important  in  judging  the  state  of  charge  of  a  battery  which  is 
partly  or  fully  charged. 

8.  A  battery  on  charge  may  be  tested  for  cell  volt&ge  by  merely 
connecting  the  terminals  from  the  fault  finder  to  the  three-volt  range  and  to 
the  connecting  straps  or  terminals.  The  reading  for  a  cell  on  charge  and  in 
good  physical  condition  should  be  2.2  volts. 

9.  The  charge  must  be  continued  until  there  is  no  further  rise  in  gravity  of 
any  of  the  cells  over  a  period  of  two  hours.  If  one  cell  is  slow  in  coming  up  to 
the  proper  point,  charge  it  individually. 

10.  .  A  cell  having  come  in  for  recharge  only  will  not  as  a  rule  require  any 
adjustment  with  acid  to  bring  it  to  the  proper  gravity  reading.  In  case  some 
of  the  electrolyte  has  been  spilled,  an  adjustment  is  necessary.  Acid  does  not 
leave  the  cell  through  evaporation.  Low  gravity  is  due  to  acid  entering  the 
plates.  Charging  drives  it  from  the  plates  into  the  solution  again  and  the 
electrolyte  returns  to  its  original  gravity. 


324  Automotive  Trade  Training 

JOB  114.     DISCHARGING  A  BATTERY, 

Very  frequently  it  is  advisable  to  discharge  a  battery.  A  discharge  test  is 
explained  in  Job  107.  Discharging  a  battery  which  has  been  charged  after  a 
long  period  of  discharged  inactivity  and  then  recharging  it  will  help  to  restore 
it  to  its  normal  activity.     To  discharge  the  battery  proceed  as  follows: 

1.  Learn  the  discharge  rate  from  the  battery  name  plate. 

2.  Secure  several  lamp  sockets  such  as  are  used  for  automobile  lighting. 
Wire  them  in  parallel,  using  enough  to  give  a  combined  draught  on  the  battery 
equal  to  the  desired  discharge  rate. 

4.  Mount  the  sockets  on  a  board  andAvire  them.  Connect  the  battery  to 
them.  By  placing  an  ammeter  in  circuit  the  discharge  rate  may  be  noted  and 
recorded. 

.  5.  Discharge  until  the  individual  cells  show  a  voltage  test  ot  1.8  each. 
Note  the  number  of  hours  elapsing  since  the  discharge  was  started.  Multiply 
this  by  the  rate  of  discharge.  Compare  the  result  with  the  rated  capacity  of  the 
battery  in  ampere-hours. 

6.  Recharge  the  battery  as  in  Job  112. 

7.  Where  a  great  deal  of  discharge  work  is  to  be  done,  a  discharging 
apparatus  utilizing  a  rheostat  is  desirable.  This  may  be  made  by  the  ingenious 
mechanic  from  some  resistance  wire.  An  ammeter  should  be  arranged  on  the 
same  panel  in  order  that  the  discharge  rate  might  be  noted  readily. 

JOB  115.     CARING  FOR  BATTERIES  IN  STORAGE. 

When  the  car  user  lays  up  his  car  for  the  winter  months,  it  is  well  for  him 
to  send  the  battery  to  the  service  station  where  it  may  receive  proper  care. 
If  a  home  charging  equipment  is  available,  he  should  follow  the  instructions 
given  below  for  a  periodic  charge  while  the  battery  is  in  wet  storage. 

Batteries  are  usually  stored  for  the  shorter  periods  in  their  normal  charged 
condition.  This  is  known  as  wet  storage.  To  keep  the  battery  in  good 
condition  it  is  necessary  to  supply  it  with  a  trickle  charge,  or  give* it  a  periodic 
charge  at  least  once  per  month.  If  the  battery  is  to  be  stored  for  a  year  it  is 
best  to  put  it  in  dry  storage.     This  means  charging  and  then  disassembling. 

Wet  Storage. — If  possible,  store  the  batteries  on  a  shelf  or  table  where 
they  may  be  charged  without  removing.  This  means  wiring  to  suit  the 
charging  equipment,  used.  Place  strips  of  wood  under  the  batteries  so  that 
they  are  not  resting  on  the  entire  surface  of  the  bottom  of  the  case.  This 
permits  of  air  circulating  through  underneath  them.  Neither  should  the  cases 
rest  tightly  against  each  other. 

Charge  the  batteries  fully  before  putting  them  in  storage  and  once  each 
month  thereafter.  Keep  the  terminals  clean  and  coated  with  vaseline.  If  the 
trickle  charge  method  of  storing  is  used  rather  than  the  periodic  charge,  the 
battery  should  be  fully  charged  before  storing.  Methods  of  charging  are  given 
in  Job  112. 

Dry  Storage. — In  this  case  the  battery  is  fully  charged.  The  electrolyte  is 
»all  drained  off  the  cells  by  turning  the  battery  bottom  up  over  a  sink  or  some 
receptacle  to  catch  the  electrolyte.  Before  draining  make  a  record  of  the 
specific  gravity  readings  for  the  cells  and  save  them  for  reference  when  putting 
the  battery  back  in  service.  After  the  electrolyte  has  all  drained  fill  the  cells 
with  distilled  water  and  allow  them  to  stand  for  five  hours.  After  this  the 
battery  is  opened  up  and  the  groups  of  plates  are  separated,  cleaned  and  stored 
in  a  clean  dry  place.  When  the  battery  is  put  in  service  it  is  given  any  needed 
repairs  and  assembled  and  recharged  as  for  the  usual  repair  or  overhaul  job. 


CHAPTER  12 
BATTERY  IGNITION 

Automotive  ignition  is  divided  into  two  distinct  classes,  battery 
ignition  and  magneto  ignition.  The  fundamental  principles  of  elec- 
tricity apply  in  each  case,  athough  the  mechanical  application  is 
different. 

Battery  Ignition. — This  division  may  be  said  to  be  subdivided 
into  two  classes,  the  vibrating  coil  and  the  plain  or  non-vibrating  coil. 
The  last  mentioned  is  the  most  used  and  is  considered  standard 
battery  ignition.  The  units  required  in  this  case  are  the  generator 
to  store  current  in  the  battery,  the  battery  to  supply  current  to  the 
coil,  the  coil  and  condenser  to  furnish  the  high  tension  spark,  the 
breaker  points,  the  distributor,  plugs,  etc. 


Fig.  364.     Cadillac   Battery   Ignition. 

Ignition  Coil. — The  spark  coil  or  ignition  coil  is  in  reality  an 
induction  coil,  in  that  the  spark  producing  igniton  of  the  fuel  charge 
in  the  cylinder  is  an  induced  current.  The  current  being  induced  is 
what  is  known  as  high  tension  current  in  that  it  is  of  sufficient  pres- 
sure or  voltage  to  cause  it  to  jump  from  one  electrode  of  the  spark 
plug  to  the  other  through  the  intervening  air  gap.  It  should  be 
remembered  that  air  is  a  poor  conductor  or  rather  an  insulator. 

Principle  of  Induction  Coil. — The  induction  coil  is  built  up  about 
a  core  of  soft  iron  wires.  These  are  bound  together  and  covered  with 
a  layer  of  paper  or  other  insulating  material.  _^  Over  this  paper  is 
wound  the  primary  or  low  tension  winding.  This  consists  of  several 
layers  of  insulated  or  enameled  magnet  wire  of  about  eighteen  gauge. 
The  ends  of  the  wire  are  later  connected  to  terminal  screws. 

325 


326 


Automotive  Trade  Training 


The  secondary,  or  high  tension  wire,  is  of  the  enameled  or  cotton 
covered  type  only  very  much  fmer.  The  number  of  turns  wound  on 
ever  the  primary  winding  runs  between  2,000  and  3,000.  This  wind- 
ing is  carefully  insulated  from  the  primary  winding  and  has  absolutely 
no  connection  with  it.  The  primary  current  or  current  drawn  from 
the  battery  cannot  and  does  not  flow  through  the  secondary  winding. 
In  it,  however,  is  induced  a  current  just  as  previously  explained  in 
Chapter  10,  except  that  instead  of  the  conductor  moving  through  lines 
of  force,  the  lines  of  force  are  caused  to  move  through  the  conductor 
windings.     To  illustrate: 

It  has  been  shown  how  in  a  bar  magnet  or  in  an  electro-magnet, 


CIRCUIT    MEMU 


Fig. 


>Go.     Technical    wiring    diagram    of    Typical    Battery    Ignition. 
(K  W  Ignition  Co.) 


which  is  what  the  core  of  iron  wire  with  its  primary  coil  really  is,  the 
current  sets  up  lines  of  force  or  flux  which  flow  from  the  north  pole 
to  the  south  pole  and  there  enter  the  iron  core  flowing  back  to  the 
north  pole  through  the  core.  Again,  they  come  out  and  flow  from 
the  north  to  the  south  pole  through  the  air  and  thence  to  the  north 
pole  from  the  south  through  the  core,  the  action  being  a  continuous, 
one  as  long  as  the  current  is  flowing  through  the  primary  winding 
from  the  battery.  However,  there  is  this  point  to  be  remembered : 
When  the  primary  current  first  starts  flowing  through  the  primary 
coil  the  lines  of  force  emanate  or  come  from  each  coil  of  the  primary 
winding.  This  happens  all  along  the  length  of  the  primary  winding 
after  which,  however,  they  all  flow  as  described  above  as  long  as  the 
current  is  not  broken.  According  to  the  same  rule,  when  the  current 
is  suddenly  broken  these  lines  of  force  flowing  about  the  coil  do  not 
continue  to  the  end  of  the  core  to  re-enter  it,  but  drop  immediately  to 
it   from   all   points,   thus   cutting   the   conductor  wound   around   the 


Battery  Ignition 


327 


primary  coil  and  known  as  the  secondary  coil.  It  is  this  action 
of  the  lines  of  force,  as  they  cut  the  conductor  composing  the 
secondary  coil  as  they  return  to  the  core,  that  is  usually  counted 
on  to  induce  the  high  tension  current  for  use  in  ignition. 
Sometimes  the  current  is  induced  when  the  lines  of  force  come 
from  the  core.  However,  this  action  is  usually  less  forceful 
and  in  general  practice  is  not  used.  Magnetization  as  a  rule 
being  slower  than  demagnetization,  the  making  of  contact  of  the 
switch  will  cause  some  current  to  be  induced  in  the  secondary  coil 
as  the  lines  of  force  leave  the  core,  but  the  voltage  or  current  is  not 
sufficient  to  cause  the  current  to  leap- the  air  gap  at  the  spark  plugs. 
When  the  switch  is  opened,  however,  the  demagnetization  is  made 


Fig.  366.     Section  of  Typical  Battery   Ignition   System.     (K  W   Ignition  Co.) 

quite  rapid  through  the  use  of  the  condenser.  Breaking  these  lines 
of  force  causes  them  to  collapse  or  break  down  very  rapidly,  and  in 
such  volume  that  a  very  high  tension  or  pressure  is  induced  within 
the  secondary  coil  which  they  are  cutting  as  they  drop  back  or  col- 
lapse. This  pressure,  varying  from  15,000  to  30,000  volts,  is  so  high 
that  it  will  jump  the  air  gap  at  the  spark  plug  points.  The  direction 
of  flow  of  the  induced  current  is  the  same  as  that  of  the  primary 
current. 

Air  Gap. — Several  air  gaps  are  in  use  with  reference  to  the  igni- 
tion system.  One  is  the  air  gap  provided  in  the  spark  plugs.  This 
air  gap  should  never  be  more  than  1/32".  Failure  of  some  other  part 
of  the  ignition  system,  such  as  the  loss  of  the  spark  plug  wire  from 
one  of  the  plugs,  might  result  in  the  high  tension  winding  of  the 
ignition  coil  being  broken  down  and  the  insulation  punctured  if  a 
s:afety  gap  were  not  provided.  This  safety  air  gap  is  usually  Y^  to 
y^'  long  and  is  built  into  the  coil.  Ordinarily  the  high  tension  spark 
is  carried  through  the  distributor  and  from  there  to  the  plug  but  the 


3^8 


Automotive  Trade  Training 


Fig.   367.     Adjusting   spark   plug   air   gap. 

safety  gap  is  always  ready  to  care  for  the  emergency.  It  is  made  of 
sufficient  size  to  insure  the  spark  going  to  the  plugs  under  normal 
conditions. 

FOR  TURNING  CONTACT  SCREW 
6  LOCK  NUT 


Pig.   368.     Adjusting   Distributor   Points    and   testing   with    thickness    gauge. 

The  resistance  of  the  air  gap  increases  with  the  compression  in 
the  cylinders.  Since  air  is  a  non-conductor,  it  is  natural  that  if  four 
times  normal  air  pressure  is  induced,  as  is  the  case  in  the  cylinder, 
the  gap  will  be  harder  to  jump. 


Fig 


Remy  Distributor  Head. 


Battery  Ignition 


329 


Timer-Distributor.  —  The  student  is  familiar  with  the  facts  of 
engine  design  with  reference  to  the  four-stroke 'principle,  and  the 
firing  order.  The  distributor  is  generally  built  to  include  the  primary 
breaker  points  as  well  as  the  means  of  distributing  the  high  tension 
current.  The  purpose  of  the  timer-distributor  is  to  make  the  electri- 
cal connection  on  the  primary  winding  of  the  ignition  coil,  thus  per- 
mitting the  magnetic  flux  to  build  up.  Next  it  must  be  broken  at 
just  the  correct  moment  to  permit  the  secondary  current  induced  to 
be  carried  back  to  the  distributor,  and  from  the  distributor  head  to 
the  plug  in  the  cyHnder  then  under  compression,  and  waiting  to  be 


Pig.    371.      Section    of   Atwater 

Kent    Distributor    Cap    and 

Kotor. 


Fig.    370.     Remy    Apperson    Igni- 
tion  Distributors. 

fired.  Here  it  jumps  the  gap,  due  to  its  tremendous  pressure  or  volt- 
age, and  ignites  the  charge.  It  will  be  noted  that  two  distinct  func- 
tions are  performed.  The  first  is  making  and  breaking  the  contacts 
for  the  completion  of  the  primary  circuit  which  might  be  said  to  be 
switching  off  and  switching  on  of  the  primary  circuit.  Normally  the 
current  is  on,  thus  permitting  the  magnetic  flux  to  build  up  to  a  high 
value  in  the  coil.  However,  the  distributor  shaft  has  a  cam  on  the 
upper  end.  On  this  cam  are  machined  as  many  lobes  as  there  are 
cylinders  to  the  engine.  This  cam  turns  at  one-half  engine  speed  so 
that  each  lobe  opens  and  closes  the  breaker  points  once  for  each  two 
revolutions  of  the  engine.  Each  time  the  switch  or  breaker  points 
are  opened,  a  cylinder  is  fired. 

Accordingly   there   must   be   an   equal   number   of   high   tension 


330 


Automotive  TradI:  Training 


Fig.  372.     Wagner  Distributor  Cap. 

wires  running  from  the  distributor  cap  to  the  engine  cylinders.  Just 
under  the  distributor  cap  is  a  rotor  which  distributes  the  high  tension 
current.  This  rotor  receives  the  high  tension  current  on  the  center 
where  it  is  usually  in  contact  with  a  spring,  and  sends  it  to  that  plug- 
wire  under  which  or  with  which  it  is  in  contact.  The  next  break  of 
the  primary  current  induces  another  high  tension  spark  which  is 
distributed  or  sent  to  the  next  plug-wire  in  line.  The  next  break 
sends  the  current  to  the  next  plug-wire,  and  so  on  and  on,  all  the 
way  around  the  cap,  four  breaks  for  the  four-cylinder  engine,  six 
breaks  for  the  six-cylinder,  and  so  on.  Needless  to  say  the  firing 
order  of  the  engine  must  be  considered  in  running  the  wires  from 


F'ig.  373A.     Stutz  Engine  with  Double  Distributor. 


I 


Battery  Ignition 


331 


the  cap.  As  far  as  the  cap  is  concerned  the  sparks  follow  one  another 
without  any  irregularity,  but  the  cylinders  may  be  fired  in  any  one 
of  several  orders.     All  that  is  necessary  is  to  find  the  proper  lobe  for 


Fig.  373B.     Stutz  Engine  with  Double  Distributor. 

the  first  cylinder  and  then  wire  it  accordingly.  After  that  take  the 
next  wire  from  the  cap  to  the  next  cylinder  to  fire,  whichever  it 
may  be. 

Spark  Control. — On  the  speed  of  the  engine  depends  to  a  certain 


332-  Automotive  Trade  Training 

extent  the  point  at  which  the  spark  should  occur.  By  means  of  the 
?park  manual  on  the  steering  column  the  distributor  head  may  be 
swung  through  a  short  arc.  This  constitutes  advancing  or  retarding 
the  spark.  In  a  motor  running  very  rapidly  the  charge  should  be 
fired  earlier  than  on  the  same  motor  running  at  a  slower  speed.  This 
has  relation  to  firing  before,  at,  or  after  T.  D.  C,  as  explained  in 
valve  timing.  In  some  cases  the  hand  control  is  depended  on  alto- 
gether to  control  the  spark  advance.  In  other  cases  this  is  all  con- 
controlled  automatically,  no  hand  control  being  provided,  or  a  com- 
bination of  the  two  is  used. 

Switches.— The  make  and  break  mechanism  of  the  car  has  been 
compared  to  a  switch,  and  such  it  is,  but  operated  in  fixed  relation 
to  the  strokes  of  the  motor.  Unless  the  motor  happens  to  stop  with 
one  of  the  lobes  under  the  breaker  point  arm,  thus  holding  the  con- 
tacts apart,  the  current  will  continue  to  flow  through  the  coil.  The 
student  will  now  grasp  the  need  of  the  resistance  unit  being  inserted 
in  the  primary  circuit.  If  it  were  not  for  this  unit  and  the  current 
continued  to  flow,  great  damage  would  be  certain  to  occur.  With  this 
measure  of  protection  the  greatest  possible  care  should  be  used  in 
all  eases,  when  stopping  the  engine,  to  turn  off  the  switch  provided. 
This  switch  usually  takes  the  form  of  a  key  arrangement  on  the  dash 
used  to  make  the  primary  circuit  complete,  or  to  break  it  when  igni- 
tion is  not  desired. 

Condensers. — In  a  general  way  the  action  of  the  condenser  has 
been  explained.  As  stated  previously,  a  condenser  is  necessary  for 
the  proper  performance  of  the  ignition  unit.  The  action  of  the  con- 
denser in  the  case  of  automotive  ignition  is  as  follows :  The  con- 
denser serves  two  definite  pur- 
poses. Current  from  the  bat- 
tery is  always  flowing  through 
the  ignition  coil  primary 
winding  except  when  the 
points  are  separated  by  action 
of  the  cam  lobes.     Since  this 

a  direct  current  flowing  V^^^^^^^^^^^^^^^^^W 
through  the  coil  it  tends  to 
keep  on  flowing  when  the 
points  are  opening.  This 
tendency  to  jump  the  gap 
would  create  quite  a  spark 
were  it  not  for  the  condenser. 

The     condenser    is     connected  Fig.    374.     Condenser   mounted   in   ease. 

across     the     contact     points.  (Wagner.) 

That  is,  a  wire  is  run  from  one  side  of  the  condenser  to  one  of  the 

contact  points,  and  another  wire  from  the  other  side  of  the  condenser 


Battery  Ignition  333 

to  the  other  side  of  the  contact  mechanism.  Novv,  when  the  points 
separate,  the  current,  instead  of  flowing  ahead  and  creating  a  spark 
PS  it  attempts  to  jump  the  gap  between  the  points,  is  sent  into  the 
condenser  which  acts  as  a  storage  reservoir.  There  is  no  electrical  con- 
nection through  a  condenser  when  it  is  in  good  condition.  If  there 
is  a  circuit  through  it  then  the  condenser  is  useless.  As  the  points 
open  and  the  current  rushes  into  the  condenser,  one  side  of  it  is 
charged  positively  and  one  negatively  at  a  rather  high  potential  or 
voltage.  This  is  due  to  the  fact  that  as  the  points  open  the  lines  of 
force  collapse,  cutting  the  coil  windings.  These  lines  of  force,  which 
must  collapse  to  give  the  spark  at  the  spark  plug,  will  also  cut  the 
primary  winding  and  induce  a  rather  high  voltage  in  it.  It  is  this 
induced  voltage  as  well  as  the  primary  voltage  which,  faiUng  to  jump 


Fig.  375.     Spark   Controls,   High   Tension   Cables   from   the   Distributor  and   Oiling 

Directions.     (Allen.) 

the  contact  points,  rushes  into  the  condenser  and  charges  it.  The 
voltage  of  this  charge  is  variously  estimated  at  from  100  to  150  volts. 
This  charge,  however,  does  not  remain  within  the  condenser.  The 
potential  is  high.  There  is  a  path  open  for  it  to  discharge  through. 
This  path  is  back  through  the  battery  and  the  primary  winding  to 
the  other  side  of  the  condenser.  Consequently  the  condenser  is  no 
more  than  charged  until  it  discharges  back  through  the  circuit  includ- 
ing the  primary  winding  of  the  coil  with  the  very  desirable  result  of 
causing  the  lines  of  force,  which  are  collapsing  about  the  core,  to 
collapse  very  much  faster.  Since  the  voltage  induced  within  the 
secondary  winding  is  dependent  on  the  rapidity  with  which  these 
lines  of  force  cut  the  many  turns  of  the  coil,  the  result  is  a  very  high 
tension  current  giving  the  desired  spark  at  the  plug.  The  student 
will  want  to  understand  that  -the  difference  of  potential  between  the 


334 


Automotive  Trade  Training 


two  sides  of  the  condenser  is  what  causes  it  to  discharge  back  through 
the  circuit.  In  shop  parlance  the  current  is  kicked  back  through. 
The  current  being  kicked  back  through  the  circuit,  which  is  in  the 
reverse  direction  from  the  initial  current,  causing  magnetism  of  the 
core,  is  a  great  help  in  completely  demagnetizing  the  core,  since  it 
overcomes  the  residual  magnetism  and  helps  to  quickly  return  the 
molecules  to  their  original  position  within  the  core.  This  entire 
action  following  the  opening  of  the  points  is  instantaneous,  the 
various  steps  following  each  other  so  closely  that  no  time  may  be 
said  to  elapse  between  them.  Reference  to  the  illustrations  will  show 
methods  and  positions  of  condenser  installation. 

Spark  Timing. — In  most  cases  the  timing  of  the  spark  to  the 
engine  is  not  a  difficult  matter  where  battery  ignition  is  used.  The 
first  thing  to  do  is  to  remove  the  distributor  cap.  Next  remove  the 
distributing  arm  and  loosen  the  set  or  cap  screw  which  appears. 
After  this  tightening  device  is  loosened,  the  cam  may  be  rotated  on 
the  stem,  or  shaft,  in  either  direction  desired  by  the  operator,  and  as 
far  as  he  desires.  It  is  well  to  remember  that  a  movement  of  a  few 
degrees  or  a  very  small  fraction  of  an  inch  is  sufficient  to  adjust  or 
put  in  time,  unless  the  trouble  is  quite  serious  and  the  motor  refuses 
to  run  at  all.  In  a  case  of  this  nature  it  would  be  necessary  to  bring 
cylinder  No.  1  onto  the  top  dead  center  compression  stroke,  and  then 
to  set  the  distributor  so  that  the  rotor  arm  when  in  position  would, 
be  so  located  as  to  bring  the  high  tension  spark  to  the  wire  running 
to  cylinder  No.  1  just  as  the  cam  lobe  was  br-eaking  the  points. 
Therefore,  if  the  car  on  the  road  gave  evidence  of  too  great  an  ad- 
vance, or  appeared  sluggish  from  too  late  a  spark,  the  proper  adjust- 
ment might  be  secured  by  lo,osening  the  binding  screw  and  moving 
the  cam  as  would  seem  necessary. 

VIBRATION  COIL  IGNITION 

Principle  of  Vibrator. — The  vibrating  coil  is  identical  in  con- 
struction with  the  non-vibrating  coil,  with  this  one  exception.     For 


mmm^m^^^^msk, 


Fig.  376.    Fordson  Vibrat-        Fibre 
Inj?  Coils. 
(K  W  Ignition  Co.) 


Put)  Rod  ConneoiMi 

Case 

Thumb  Nut 

Contact  Poinr 
Roller  Arm 
Brush 

Engine  Cover 


Pig.  ."iTT.     Ford  Timer. 


Battery  Ignition  335 

the  breaker  points  within  the  distributor  head  which  are  worked 
mechanically  and  in  fixed  relation  to  the  firing  order,  the  vibrating 
coil  utilizes  a  vibrator  mounted  on  the  coil.  The  vibrator  consists 
of  a  set  of  springs  and  conductors,  and  a  set  of  contact  points,  fre- 
quently called  vibrator  points.  When  contact  is  made  within  the 
timer,  which  takes  the  place  of  the  distributor,  a  primary  current  is 
sent  through  the  primary  winding  of  the  coil.  This  causes  a  mag- 
netic pull  at  the  end  of  the  iron  core  and  thus  attracts  or  pulls  to  it 
the  steel  spring  on  which  is  mounted  one  contact  point.  When  this 
point  is  pulled  away  from  the  other,  the  primary  circuit  is  broken  or 
interrupted  just  as  happened  when  the  contact  points  were  opened 
in   the   distributor   head.     The   consequent   action    again    is    similar. 


Fig.   378.     Oiling   Ford   Timer. 

That  is,  the  breaking  of  the  primary  circuit  causes  the  lines  of  force 
to  collapse,  inducing  a  high  tension  current  in  the  secondary  winding 
which  is  carried  to  the  spark  plug,  there  to  ignite  the  fuel  charge. 

However,  as  soon  as  the  magnetic  effect  of  the  iron  core  is 
broken  down  due  to  the  breaking  of  the  points,  the  cessation  of 
primary  current,  and  the  condenser  kicking  back  through  the  primary 
coil,  the  steel  spring  snaps  the  contact  back  in  plkce,  again  permitting 
ihe  primary  current  to  flow.  This  again  causes  the  contact  to  be 
broken,  another  induction  of  high  tension  current  to  take  place,  and 
another  spark  to  be  delivered  to  the  same  plug.  These  actions  or 
operations  follow  each  other  so  rapidly  that  there  is  what  appears  to 
be  a  continuous  flow  of  high  tension  current  jumping  the  spark  plug 
points  as  long  as  the  roller  within  the  timer  is  in  contact  position. 
Since  this  system  is  that  in  use  on  the  Ford  car,  the  student  is  likely 
more  or  less  famihar  with  it. 

Timer. — A  timer  instead  of  a  distributor  is  used.  This  is  some- 
times called  the  commutator.     A  roller  with  spring  tension  is  mounted 


336 


Automotive  Trade  Training 


on  the  cam  shaft  where  it  travels  at  one-half  crank  shaft  speed. 
Within  the  timer  head  are  mounted  four  (in  the  case  of  the  Ford, 
this  depends  on  the  number  of  cylinders)  strips  of  metal  or  contacts. 
The  roller  makes  contact  and  electrical  connection  for  the  primary 


s  1^3  Sir 

3  oQQCoaO  u 

5    —  PM  r^  T»-    C 


ft>  «C    b:    t:    fc    is 

•^       <^      nn     rJ\     rA    Gt 


oOSt^S\"2<^^     2  2    3:3 

*=-^-.-2opc.^     op  ooE« 


current  through  these  strips.  Each  timer  contact  is  connected  to  a 
separate  coil  on  the  coil  box  carrying  primary  current  from  the 
magneto  to  it.  As  the  roller  rolls  around  on  the  inside  of  the  timer 
head,  one  after  the  other  of  the  coils  are  connected  to  it  through  the 
segments.     As  each  one  in  turn  is  brought  into  action  the  high  ten- 


Battery  Ignition 


Z31 


sion  current  is  Induced  through  the  action  explained  above.  Each 
coil  is  connected  to  one  spark  plug  only.  Whenever  the  roller  is  in 
contact,  and  for  as  long  as  it  is  in  contact  with  its  segment,  that  coil 
sends  a  spark  to  its  plug.  The  essential  difference  between  the 
vibrating  and  non-vibrating  coils  is  that  the  last  mentioned  gives 
one  pulse  of  high  tension  current  to  jump  the  spark  plug  points 
while  the  vibrating  coil  gives  a  series  of  pulses  of  high  tension 
current  to  jump  the  plug  points  for  each  firing  effort.  In  the  case  of, 
the  non-vibrating  coil,  the  break  of  the  contact  points  depends  on  the 
mechanical  operation  of  the  breaker  points,  a  cylinder  fired  for  each 
break.  In  the  case  of  the  vibrating  coil  the  break  of  the  points  is 
entirely  automatic,  but  at  the  same  time  this  automatic  action  is  con- 
trolled by  the  roller  within  the  timer  head. 

Timing  the  Spark. — The  timing  of  the  spark  as  mentioned 
previously  is  largely  dependent  on  the  rolling  of  the  roller  within 
the  timer,  in  relation  to  the  cam  shaft  speed.  Advance  and  retard  of 
the  spark  are  obtained  from  rotating  the  timer-head  forth  and  back 
on  its  seat.  Needless  to  state,  the  wires  connected  to  the  coils  are 
made  flexible  and  permitted  to  move  with  the  timer-head. 

As  to  the  method  of  securing  the  spark  in  the  proper  cylinder: 
In  this  case  the  primary  wires  must  be  led  from  the  timer  to  the 
proper  coil  to  give  the  high  tension  spark  in  the  desired  cylinder. 
That  is,  coils  and  timer  must  be  connected  in  relation  to  coils  and 
cylinder.  The  whole  must  be  in  proper  relation  to  timer  roller  and 
compression  stroke. 

JOB  lie.     ATWATER  KENT  IGNITION 
SYSTEM,  TYPE  CC. 

This  system  as  used  on  the  Maxwell  car 
is  of  the  closed  circuit  type  differing  radi- 
cally from  the  K-2  system.  The  amount  of 
current  consumed  for  ignition  is  very  much 
greater.  Inasmuch,  however,  as  the  gener- 
ator is  producing  current  at  all  times  this 
drain  is  not  serious.  The  closed  circuit  sys- 
tem for  battery  ignition  is  used  to  such  an 
extent  that  it  might  be  said  to  be  the  stan- 
dard battery  system.  The  coil  and  the 
contact  maker  and  distributor  constitute  the 
CC  system.  ' 

Contact  Maker. — The  contact  maker 
consists  of  an  exceedingly  light  contact  arm 
made  from  steel.  The  end  of  this  arm  rests 
lightly  on  the  hardened  steel  cam  which  is 
driven  at  one-half  crank  shaft  speed.  The 
cam  has  four  points  opening  the  contact 
points  four  times  for  each  two  revolutions 
of  the  engine  which  is  necessary  for  firing 
Fig.  sm.    Atwater  Kent  Type  ^he     four-cycle    engine    of    four    cylinders. 

"CC"  Ignition  Unit.  Each  time  the  pomts  are  opened  the  primary 


338 


Automotive  Trade  Training 


circuit  is  broken,  thereby  inducing  a  high  tension  current  in  the  secondary- 
winding, '  which  is  led  through  the  distributor  to  the  spark  plugs.  The  con- 
denser is  mounted  directly  on  the  contact  maker.  This  construction  tends 
to  simplify  the  construction  and  increase  the  life  of  the  contact  points. 

The  high  tension  distributor  forms  the  top  of  the  instrument.  The  high 
tension  rotor  takes  the  jump  spark  current  from  the  center  terminal  and 
distributes  it  to  the  plugs  in  proper  firing  order. 

Coil. — This  is  of  the  usual  non-vibrating  type  of  construction.     An  iron 

icore  has  two  windings  on  it.     The  coarse  winding  or  primary  is  next  to  the 

iron  core.     Over  this  are  wound  the  many  turns  of  fine  insulated  wire  forming 


Fig.  381.    Maxwell  Atwater  Kent  Ignition  System. 

the  secondary  winding.  The  amount  of  current  used  is  automatically  regulated 
by  the  resistance  unit  in  the  top  of  the  coil.  The  coil  is  carefully  sealed  to 
exclude  moisture. 

Setting  and  Timing  the  Type  CC  System. — First  make  certain  that  all 
advance  rods  and  electrical  connections  are  complete.  Advance  rods  must  be 
so  adjusted  that  the  full  advance  movement  of  the  distributor  is  possible*. 
With  these  precautions  first  taken,  proceed  as  follows: 

1.  After  wiring  is  complete  remove  the  plugs  and  lay  them  on  th< 
cylinder  head.  Have  the  plug  wires  attached.  Do  not  permit  the  termina 
ends  of  the  plug  to  touch  the  casting. 


Battery  Ignition  339 

z.  Turn  on  the  ignition  switch  and  crank  the  motor  over  slowly  using 
the  hand  crank.  Note  that  each  of  the  plugs  sparks  in  the  proper  firing  order. 
For  the  Maxwell  this  is  1-3-4-2.     When  this  is  checked,  turn  off  the  ignition. 

3.  Set  the  spark  lever  on  the  steering  wheel  quadrant  one  and  one-fourth 
inches  from  the  full  retard  position. 

4.  Loosen  the  ignition  coupling  so  that  the  knurled  collar  on  the  hori- 
zontal shaft  may  be  easily  turned. 

5.  With  the  hand  crank  turn  the  motor  over  until  the  piston  in  No.  1 
cylinder  is  on  exact  T.  D.  C.  between  the  compression  and  power  strokes. 

6.  Turn  the  ignition  on  again. 

7.  With  the  fingers  or  the  point  of  a  screw  driver  move  the  knurled  collar 
away  from  you  or  toward  the  engme,  very  slowly  and  carefully  until  a  spark 
is  seen  to  jump  plug  No.  1.  Do  this  so  carefully  that  the  knurled  collar  stops 
the  instant  the  spark  occurs.  If  not  certain  of  the  operation,  move  the  collar 
back  one-quarter  turn  and  try  again. 

8.  Stop  exactly  as  the  spark  occurs.  Maintain  the  parts  in  this  position 
until  the  adjustment  can  be  secured  by  locking  the  hexagonal  screw  on  the 
coupling  clamp. 

The  motor  is  then  timed  so  that  the  spark  occurs  on  dead  center  when  the 
spark  lever  is  placed  one  and  one-fourth  inches  from  full  retard.  This  allows 
of  ten  degrees  retard  for  safe  starting  and  about  twenty  degrees  advance  for 
high  speeds. 

Adjusting  Contact  Points. — If  convinced  beyond  doubt  that  the  contact 
points  are  at  fault,  they  should  be  adjusted.  The  normal  gap  between  the 
points  should  not  be  less  than  .005"  nor  more  than  ,008".  The  standard  setting 
is  ,006". 

The  contact  points  are  made  from  purest  tungsten  and  are  much  harder 
than  platinum  iridium  previously  used. 

JOB  117.     ATWATER  KENT  IGNITION  SYSTEM  K-2. 

In  this  system  which  operates 
on  the  open  circuit  principle  there 
are  three  units.  The  Unisparker 
which  combines  the  special  form  of 
contact  maker  which  is  the  basic 
principle  of  this  system,  and  the 
distributor  for  the  high  tension 
current.  The  Coil,  which  consists 
of  the  usual  primary  and  secondary 
winding,  i.s  imbedded  in  a  special 
insulating  compound.  The  coil  is 
Fig.  382  View  of  contact  malver  showing  of  the  non-vibrating  type.  The 
places  to   be  oiled.— Type   K2.  .  •,    ■     .1       •       •^-  -^  i. 

other  unit  is  the  ignition  switch. 

Principle  of  Operation. — The  operation  of  the  system  is  illustrated  in  Figs. 
384,  385,  386,  and  387.  A  notched  shaft  is  provided,  one  notch  for  each  cylinder. 
This  shaft  travels  at  one-half  engine  speed  so  as  to  provide  the  four  sparks  for 
each  two  revolutions  of  the  engine.  A  lifter  or  trigger  is  operated  by  the 
rotation  of  the  shaft  being  pulled  forward.  A  spring  attached  to  the  trigger 
pulls  it  back  to  position.  A  hardened  steel  latch  and  a  pair  of  contact  points 
complete  the  instrument. 

In  Fig.  385  the  lifter  is  being  pulled  forward  by  the  notched  shaft.  When 
pulled  forward  as  far  as  the  shaft  will  carry  it,  the  lifter  is  snapped  back  into 
its  original  position  by  the  spring.  In  returning,  it  strikes  against  the  latch 
throwmg  this  against  the  contact  spring,  thus  closing  the  contact  points  for  a 


wt      -■Pr^^'ySff'Ficl.^    I  1  OIL 

tlGHTLY 


SEE  THAT 
CONTACT-POINTS 
ARC  FREE  FROM  OIL 


340 


Automotive  Trade  Training 


wwv— 


BATTKRV 


CONTACT  MAKER 

Fig.  383.     Atwater  Kent  Wiring  Diagram— Type  K2. 

very  brief  instant.  The  contact  is  made  for  such  a  small  space  of  time  that  the 
eye  cannot  follow  the  action.  This  is  quite  different  frorri  the  closed  circuit 
type  where  the  contact  is  made  and  considerable  time,  is  allowed  for  building 
up  the  magnetic  field  about  the  coil  core. 


Fig.   386.    Contact  Made. 


Fig.  385.     Contact  Still  Open. 


Fig.   387.     Contact   Broken. 


In  Fig.  387  the  lifter  has  dropped  into  the  second  notch.  The  student  will 
note  that  the  circuit  is  closed  only  during  the  instant  of  the  spark.  No  current 
will  flow  at  any  other  time  not  even  if  the  switch  is  left  on  with  the  motor 
standing  idle. 

The  engine  speed  has  nothing  to  do  with  the  speed  with  which  the  contact 
is  made  and  broken.     No  matter  how  fast  the  engine  may  be  operating  the 


Battery  Ignition 


341 


spring  will  always  return  the  lifter  at  the  same  speed.     This  return  speed  is  the 
vital  factor  in  making  and  breaking  the  primary  circuit. 

Contact  Points. — The  contact  points  are  the  only  parts  adjustable  and  they 
require  this  at  infrequent  intervals.  The  normal  gap  is  from  .010"  to  .012", 
never  closer.  These  points  are  made  from  pure  tungsten.  When  working 
properly,  small  particles  of  tungsten  will  be  carried  from  one  point  to  the  other, 
sometimes   forming  a   roughness  and  dark  gray   color   on   the   surface.     This 


9Arrrnm 
Fig.    388.      Wiring   Dia- 
gram, Type  "K-2"  or  "H", 
with  Plate  Switch  or  Kick 
Switch  Coils. 


Fig.  389.  Wiring  Dia- 
gram, Type  "K-2"  or  "H", 
with  Underhood  Coil  Re- 
versing  Switch. 


roughness  does  not  in  any  way  aflfect  the  working  of  the  pomts  owing  to  the 
fact  that  the  rough  surfaces  fit  into  each  other.  However,  if  it  becomes 
necessary  to  adjust  the  points  the  rough  parts  must  be  removed.  To  do  this 
remove  the  contacts  from  the  Unisparker  and  file  the  points  with  a  fine  file. 
When  reassembled,  the  mechanic  will  want  to  see  that  the  points  have  a  proper 
bearing  over  their  entire  surface. 

Oiling. — The  other  parts  of  the  contact  maker — the  latch,  the  lifter,  lifter 
spring  and  notched  shaft  are  not  subject  to  wear  if  they  are  properly  cleaned 
and  oiled  at  intervals  of  a  few  weeks.  Under  no  circumstances  permit  oil  to 
get  on  the  contact  points.     Refer  to  Fig.  381  for  oiling  instructions. 


i 


342 


Automotive  Trade  Training 


Setting  and  Timing. — First  put  piston  No.  1  on  top  dead  center  com- 
pression stroke.  Loosen  the  clamp  holding  the  Unisparker  in  position.  Next 
turn  the  instrument  backward,  contrary  to  the  direction  of  normal  rotation, 
until  a  click  is  heard.  This  click  occurs  at  the  exact  instant  of  the  spark. 
Maintaining  the  Unisparker  at  this  position  it  should  again  be  secured  by 
tightening  the  clamp. 

The  distributor  cap  is  now  removed  and  the  terminal  in  contact  with  the 
distributor  block  is  connected  to  cylinder  No.  1.  Connect  the  other  cylinders 
in  their  proper  order  of  firing. 

JOB  118.     NORTH  EAST  IGNITION  SYSTEM  FQR  DODGE  CARS. 

MODEL  O. 


Fig.  390.    Dodge   North   East   Ignition   System. 

The  ignition  distributor  is  mounted  on  the  right-hand  side  of  the  engine, 
being  held  in  position  by  four  bolts.  There  are  two  shafts,  one  a  horizontal 
driven  from  the  engine,  and  the  other  a  vertical  driven  from  the  horizontal  one. 
The  latter  is  driven  from  the  pump  shaft  through  a  flexible  coupling.  It  is 
driven  at  engine  speed.     The  vertical  shaft  travels  just  one-half  as  fast,  the 


Fig.  391.    Dodge  North  Bast  Ignition   System. 


Battery  Ignition 


843 


reduction  of  speed  being  through  the  spiral  gears.  The  complete  distributor 
unit  consists  of  three  self-contained  assemblies.  The^e  are  the  ignition  coil, 
the  breaker  box  and  distributor  head  assembly,  and  the  distributor  base 
assembly  which  includes  the  automatic  spark  advance  mechanism.  Any  one  of 
the  three  elements  may  be  removed  from  the  distributor  unit  without  disturbing 
the  other  two. 

Ignition  Coil  Assembly. — This  is  illustrated  in  Fig.  394.  It  is  so  con- 
structed and  designed  as  to  operate  on  the  twelve-volt  starting  and  lighting 
circuit.  The  coil  is  not  likely  to  cause  any  trouble  and  when  this  does  occur  the 
entire  assembly  is  usually  replaced.  For  tests  on  coils  refer  to  Jobs  122  and 
130. 

Breaker  Box  and  Distributor  Head  Assembly. — If  for 
any  reason  the  distributor  head  and  breaker  box  is  to  be 
removed,  ficst  place  the  distributor  in  full  retard  position. 
Next  remove  the  distributor  head.  Mark  the  exact  posi- 
tion of  the  distributor  rotor  on  the  edge  of  the  box.  This 
njark  should  be  made  with  special  care,  because  it  has  to 
serve  as  the  sole  guide  for  the  correct  position  of  the 
vertical  shaft  when  the  assembly  is  put  back  in  place  on 
the  distributor-base.  Moreover,  while  the  breaker-box 
assembly  is  separated  from  the  base,  the  horizontal  shaft 
in  the  base  must  not  be  turned  from  the  position  it 
occupied  at  the  time  when  the  location  of  the  rotor  was 
marked.  If  either  of  these  precautions  is  neglected,  the 
correct  relationship  between  the  several  moving  parts  of 
the  system  will  very  probably  be  disturbed  to  such  an 
extent  that  a  complete  retiming  of  the  distributor  will 
become  necessary. 

The  breaker  box  contains  the  condenser  as  well  as  the  breaker  contacts 
and  breaker  cam.  The  distributor  head  covers  the  entire  box  excluding  water, 
cil  and  dirt. 


Fig'.  392.  Breaker- 
Box  and  Distribu- 
tor-Head   Assembly. 


-Fig.  393. 
Distributor-Head. 


Fig.  394.     Ignition 
Coil  Assembly. 


Breaker  Contacts. — The  breaker  arm  carrying  one  of  the  breaker  contacts 
is  mounted  on  a  pivot  from  which  it  is  thoroughly  insulated  by  a  fiber  bushing. 
The  coil  spring,  which  is  attached  to  the  lug  at  the  pivot  end  of  the  arm,  holds 
it  in  such  position  as  to  keep  the  points  closed,  making  the  system  a  closed 
circuit  system.  The  fiber  block  mounted  near  the  center  of  the  breaker  arm 
is  struck  by  each  lobe  on  the  breaker  cam,  in  turn,  and  the  points  are  separated. 
This  produces  the  four  interruptions  of  the  primary  circuit  necessary  to  the 
production  of  the  four  high  tension  sparks,  for  each  two  revolutions  of  the 
engine. 

The  second  contact  is  carried  by  the  stationary  contact  stud  which  is 
adjustably  mounted  , in  an  arched  support.     With  this  stud  properly  adjusted, 


344 


Automotive  Trade  Training 


a^VAV^A 


the  distance  between  the  contact  points  when  they  are  fully  separated  by  the 
cam  is  .020". 

Replacement  of  Breaker  Contacts. — The  proper  method  is  to  replace  the 


Battery  Ignition 


345 


.  Fig.  396.    Model  O  Ignition  Distributor. 

entire  breaker  arm  and  stationary  stud  assemblies.  The  breaker  arm  can  be 
removed  by  simply  lifting  it  off  its  pivot  after  its  pigtail  has  been  disconnected 
from  the  breaker-box  binding  post.  The  spring  attached  will  slip  off  of  its  own 
accord  as  soon  as  the  arm  is  raised  sufficiently  from  its  normal  position.  After 
the  breaker  arm  has  been  taken  off,  the  stationary  contact  stud  can  be  removed 
by  releasing  its  lock  nut  and  unscrewing  it  from  its  support.  Reverse  the 
operations  to  replace. 


Fig.   397.     Breaker-Box. 


Automatic  Spark  Advance. — Combustion  does  not  follow  instantaneously 
on  the  occurrence  of  the  spark,  however,  because  a  small  interval  of  time  is 
always  needed  for  the  gas  in  the  cylinder  to  ignite.  Consequently,  unless  soma 
means  were  provided  for  offsetting  the  lag  between  the  spark  and  combustion, 
the  explosion  of  gas  could  not  always  be  made  to  take  place  at  the  right 
moment  under  the  varying  speeds  of  the  motor.  The  centrifugally  actuated 
mechanism  shown  in  Fig.  399  is  designed  to  care  for  this  by  automatically 
advancing  and  retarding  the  time  of  the  spark  in  exact  accordance  with  the 
speed  at  which  the  engine  is  running. 


346  Automotive  Trade  Training 

Manual  Spark  Control.— This  works  independent  of  the  centrifugal  device. 
It  is  used  principally  for  starting  or  idling  the  engine,  or  to  facilitate  carburetor 
adjustments.  In  normal  driving  the  correct  method  of  use  is  to  advance  the 
manual  control  as  far  as  the  engine  will  permit  without  knocking  and  permit 
it  to  remain  at  that  position. .  The  actual  regulation  of  the  advance  and  retard 
is  then  cared  for  by  the  automatic  device.  When  properly  set  with  reference 
to  the  cam  position  the  retarding  of  the  spark  lever  permits  the  spark  to  occur 
eight  degrees  past  top  dead  center.  With  the  spark  lever  advanced  the  spaik 
will  occur  fifteen  degrees  before  top  dead  center. 

Timing  the  Distributor.— First  bring  the  piston  in  No.  1  cylinder  to  top 
dead  center,  and  advance  the  hand  crank  caVefully  until  it  is  just  starting  down. 


Fig.    39S.     Ignition   Distributor   with   Test   Lamp   Attached — Ground    Return    System. 
Rotor  in   position  for   Spark  to  occur  in   No.  1   Cylinder. 

To  be  certain  of  this  it  is  best  to  do  the  work  with  the  cylinder  head  removed. 
The  mechanic  may  use  some  method  which  does  not  require  the  removal  of  the 
head  but  should  be  certain  that  the  position  is  correct.  Next,  remove  the 
control  from  the  breaker-box  arm  and  retard  it  fully  by  moving  it  as  far  as  it 
will  go  in  the  direction  of  rotation  of  the  vertical  shaft.  With  the  ignition 
switch  in  off  position,  the  distributor  head  and  distributor  rotor  may  be 
removed.  The  breaker-cam  nut  may  be  backed  off  by  means  of  a  screw  driver 
with  a  blade  wide  enough  to  catch  both  sides  of  the  nut  at  one  time.  This  wHl 
leave  the  cam  free  to  rotate  on  its  shaft.  Next  replace  rotor  and  turn  the  cSini 
slowly  until  the  breaker  points  just  begin  to  open  when  the  rotor  occupies  the 
position  where  it  normally  makes  contact  with  the  No.  1  distributor  terminal. 
Refer  to  Fig.  398  which  Shows  the  distributor  and  rotor  in  this  position. 


m 


Fig.  399.     Automatic  Advance  Mechanism  on  Shaft. 

This  adjustment  can  often  be  facilitated  by  turning  the  cam  forward  to 
separate  the  contacts,  and  then  back  agai.i  slowly  until  the  contacts  just  come 
together,  at  which  point  the  cam  should  be  allowed  to  remain.  When  the 
proper  position  for  the  cam  is  assured  the  rotor  should  be  removed  again  and 
the  cam  locked  in  position  by  tightening  the  slotted  nut  which  holds  it. 
Replace  the  rotor  and  rock  the  vertical  shaft  back  and  forth  as  far  as  the  slack 
in  the  gears  will  permit,  noting  carefully  the  action  of  the  breaker  contacts. 
The  setting  must  be  so  accurate  that  as  the  gears  are  rocked  forward  to  take 
up  the  slack  the  contacts  will  just  separate,  and  yet  when  the  gears  are  rocked 
backward  the  points  will  actually  close. 

Using  Lamp  Bulb  to  Check  Timing. — A  convenient  method  of  verifying  the 
ignition  timing  is  to  use  a  twelve  to  sixteen  volt  bulb  connected  as  shown  in  the 
illustration,  Fig.  398.    When  the  contacts  separate,  the  bulb  will  light.    When 


Battery  Ignition 


347 


the  contacts  are  closed  the  current  all  passes  through  the  ignition  unit  and  the 
lamp  does  not  light.  The  instant  of  opening  and  closing  of  the  points  is  very 
evident  as  indicated  in  the  bulb.  This  test  may  be  applied  to  any  battery 
system  if  care  is  used  in  selecting  the  correct  size  of  bulb  and  the  points  of 
connecting  the  wires  to  put  it  into  circuit  across  the  contact  points.  In  general 
it  might  be  said  that  when  a  grounded  return  is  used  one  cable  is  grounded, 
while  where  a  two-wire  or  insulated  return  is  used  the  proper  terminals  must 
be  located  and  used. 

JOB  119.     HUDSON  DELCO  IGNITION. 

The  ignition  unit  is  located  above  the  timing  gears  of  the  Super  Six  motor. 
It  is  driven  by  spiral  gears  from  the  pump  shaft.     The  distributor  head  is  of 


A3.i.  t,T'NG    NU 


LOCKING    SCREW 


CONTACT   POINT 


SCREW    FOR 

CAM 
ADJUSTMENT 


BREAKER   ARM 


CONDENSER 


RESISTANCE    UNIT 


Fig.  400.    Hudson  Delco  Distributor. 

the  usual  constant  contact  type.  Beneath  the  distributor  head  and  rotor  is  the 
timer.  By  loosening  the  screw  in  the  center  of  the  shaft  it  is  possible  to  time  the 
ignition.  By  moving  the  cam  in  a  clockwise  direction  the  timing  is  advanced, 
and  by  moving  the  cam  in  a  counter-clockwise  direction  the  spark  is  retarded. 

The  proper  gap  for  the  contact  points  is  .018".  If  it  should  be  necessary  to 
clean  the  contact  points  use  a  strip  of  fine  sandpaper  pinched  between  the 
points. 

A  top  view  of  the  timer  mechanism  is  shown  in  Fig.  400.  In  this  figure 
the  rotor  and  the  distributor  head  are  removed. 

A  side  view  of  the  unit  is  shown  in  Fig.  401.  Note  the  automatic  spark 
advance. 

Timing  and  Ignition. — Set  the  spark  lever  on  the  steering  wheel  at  the  top, 
making  certain  that  all  parts  are  in  proper  working  condition  for  full  movement 
of  the  advance  and  retard  mechanism  as  effected  manually. 


348 


Automotive  Trade  Training 


Open  the  priming  cocks  and  set  piston  No.  1  on  top  dead  center  of  the 
compression  stroke. 

No.  1  cylinder  is  due  to  fire  in  advance  position  when  the  mark  A  on  the 
flywheel  reaches  the  pointer  attached  to  the  crank  case.  This  may  be  observed 
through  the  inspection  hole  on  the  flywheel  housing,  left  side  motor.  Mark 
"A"  is  one-half  inch  before  top  dead  center.  Top  dead  center  is  marked  D.  C. 
1  and  6. 

Loosen  cam  and  set  to  break  at  this  point.  Make  certain  that  the  adjusting 
screw  is  set  properly  so  as  to  prevent  a  change  in  timing. 

The  spark  occurs  the  instant  the  contact  points  open.  In  checking  the 
timing  hold  the  cam  on  tension  in  the  opposite  direction  of  rotation  in  order 
that  all  backlash  be  removed  from  the  gears. 


CONTACT   BUTTON 


Fig.   401.     Hudson    Delco    Automatic    Advance   Mechanism. 

After  retiming  and  rechecking  the  timing  of  the  opening  of  the  breaker 
points,  the  head  may  be  replaced.  Place  a  bit  of  vaseline  on  the  rotor  track 
so  that  no  wear  may  occur. 

Coil. — The  coil  is  of  the  usual  non-vibrating  high  tension  induction  type. 
It  is  mounted  on  the  dash. 


I 


JOB  120.     BUICK  DELCO  IGNITION. 

The  distributor  timer  is  mounted  on  the  front  end  of  the  motor  generator. 
It  is  driven  by  a  spiral  gear  which  is  cut  in  the  outer  face  of  the  generator 
driving  clutch.  The  driving  gear  is  operated  by  the  pump  shaft  at  one  and 
one-half  times  engine  speed.  This  in  turn  drives  the  vertical  shaft  of  the 
distributor  at  one-half  engine  speed.  The  vertical  shaft  carries  the  breaker 
cam,  the  rotor,  and  the  automatic  advance  mechanism. 


Battery  Ignition 


349 


ADVAf/CE^EVEH 


Z.EAOTO  COIL 


B/TEMKEROin 


OILER. 


tONTRCT  ftRn 
CENTER  CONT/ICT. 


l^OTO/f. 


ROTOf?  BOTTOM. 


BALL  BERRINQ^ 


Fig.  402.     Buick   Delco   Ignition   Unit. 


360  Automotive  Trade  Training 

Spark  Control.— The  distributor  is  equipped  with  both  manual  and  auto- 
matic spark  control.  The  manual  control  is  used  for  retarding  the  spark  in 
starting  and  very  slow  idling,  as  well  as  the  necessary  advance  for  low  engine 
speeds  when  the  automatic  advance  is  not  operative. 

Adjusting  Timing  Contacts. — The  contact  points  when  fully  open  should 
measure  just  .018".  The  adjustment  is  effected  by  loosening  the  adjustment 
nut  and  screw  shown  in  the  top  of  Fig.  402.  Make  certain  the  lock  nut  is 
properly  tightened  after  adjustment  is  completed. 

Timing  the  Ignition. — First  place,  the  spark  lever  on  the  steering  wheel  in 
the  fully  retarded  position.  Next  turn  the  engine  to  the  seven-degree  mark 
which  is  practically  one  inch  after  top  dead  center  with  engine  on  compression 
stroke  for  cylinder  No.  1.  The  timing  adjustment  screw  in  the  center  of  the 
distributor  shaft  is  loosened  and  the  breaker  cam  is  turned  so  that  the  rotor 
button  will  be  in  position  under  high  tension  terminal  No.l  when  the  distributor 
head  is  properly  located.  This  determines  the  proper  lobe  of  the  cam  to  use 
for  timing. 

In  attempting  to  locate  the  point  at  which  the  cam  must  be  set  use  the 
following  plan.  Set  the  cam  so  that  when  the  slack  in  the  distributor  gears  is 
rocked  forward  the  contacts  just  open.  When  the  slack  in  the  gears  is 
removed  by  rocking  backward  the  contacts  will  just  close. 

Tighten  the  adjustment  screw  with  the  parts  in  this  position.  Replace  the 
rotor  and  the  head.  The  firing  order  is  1-4-2-6-3-5.  Test  all  high  tension  wires 
to  see  that  the  proper  wire  leads  to  each  cylinder  in  turn. 

Resistance  Unit.— The  resistance  unit  is  mounted  on  the  forward  end  of 
the  ignition  coil.  It  consists  of  a  special  resistance  wire  wound  on  a  porcelain 
spool  and  connected  in  series  with  the  primary  winding.  This  connection 
appears  in  the  circuit  diagram  Fig.  395.  It  serves  the  purpose  of  preventing 
an  excessive  discharge  from  the  storage  battery  when  the  engine  is  not 
running,  and  the  ignition  switch  is  on  with  the  contact  points  closed.  It  also, 
through  current  regulation,  insures  a  more  even  spark  at  the  varying  engine 
speeds. 

JOB  121.    PIERCE  ARROW  DOUBLE  DISTRIBUTOR. 

The  Pierce  Arrow  car  uses  a  T  head  motor  and  provides  double  ignition. 
The  ignition  switch  is  so  arranged  that  either  double  or  single  ignition  may  be 
used  at  the  option  of  the  driver.  Two  sets  of  plugs,  condensers,  breaker  points, 
transformer  coils,  etc.,  are  used. 

The  double  system  is  used  except  when  testing  one  system  independent 
from  the  other  or  when  the  battery  may  be  very  low.  The  idea  of  the  double 
ignition  application  to  the  Pierce  engine  is  to  have  the  charge  within  the 
cylinder  fired  at  two  points  simultaneously  thus  insuring  rapid  and  complete 
flame  propagation. 

An  automatic  advance  is  provided,  the  action  being  similar  to  the  auto- 
matic advance  for  the  single  distributor  head. 

Care  and  Maintenance. — The  battery  breaker  points  KL  and  EP,  Fig.  403, 
should  be  set  to  open  .015".  These  points  are  of  pure  tungsten.  They  require 
little  attention.  If  they  do  not  give  perfect  contact  after  adjustment  they  may 
be  put  into  service  and  in  a  little  while  will  true  themselves  up  as  they  wear. 

Before  putting  a  new  car  in  service,  and  occasionally  thereafter,  it  is  advis- 
able to  place  a  bit  of  vaseline  on  the  track  of  the  contact  buttons  within  the 
bakelite  head.     Remove  any  surplus  with  a  dry  cloth. 

The  fiber  cams  F  and  J  will  wear  a  bit  during  the  first  1000  miles  and  it  may- 
be necesary  to  adjust  the  points  to  remedy  this.  Thereafter  very  little  wear 
will  occur  at  this  point. 


Battery  Ignition 


351 


C     D 


E  FG  H         I 


Fig.  403.     Pierce  Arrow  Double  Distributor   (Delco). 

If  it  is  desired  to  make  the  points  open  a  bit  nearer  exact  synchronism  it 
can  be  accomplished  by  loosening  the  screws  D,  D,  and  D,  Fig.  403,  on  the  sub- 
base  to  which  the  breaker  mechanism  is  attached.  The  equalization  is  then 
effected  by  moving  the  sub-base  about  until  the  desired  result  is  obtained. 

It  may  be  noted  by  examining  the  bakelite  distributor  tops  or  heads  that 
the  firing  order  is  imprinted  on  them,  with  the  proper  cylinder  number  opposite 
each  terminal. 

Timing  the  Spsirk. — For  timing  this  double  ignition  unit  to  the  engine, 
first  place  the  flywheel  so  that  the  indicator  is  over  the  ignition  mark  on  the 


352 


Automotive  Trade  Training 


flywheel  as  shown  in  Fig,  404,  being 
careful  to  have  the  engine  on  the  com- 
pression stroke  for  cylinder  No.  1.  The 
distributing  arms  in  the  Delco  Unit, 
Fig.  403,  should  then  be  in  position  to 
fire  cylinder  No.  1,  as  marked  on  the 
head  of  the  distributing  units.  With 
the  spark  fully  retarded  on  the  quad- 
rant, both  sets  of  points  should  just  be 

on  the  point  of  opening.     In  this  posi-  „.       .^.     „.  .  ^.    . 

.,         J-  ^  -u   ^-  V       1        ij     1  ^^S-  404.     Pierce  Arrow  Timing 

tion    the    distributing    unit    should    be  Diagram. 

connected  to  the  driving  flange  on  the  pump  shaft. 

To  make  a  slight  adjustment  of  the  timing,  to  make  the  points  open  a  bit 

earlier  or  a  bit  later,  the  instrument  is  not  disconnected  from  the  pump  shaft 

coupling,  adjustment  being  made  by  loosening  the  adjusting  screw  G  instead. 

With  this  screw  loosened  the  cam  may  be  adjusted  to  make  the  points  break  at 

the  proper  time.     Care  should  be  used  to  see  that  the  cam  is  not  moved  through 

more  than  a  very  slight  angle.     If  it  is  moved  any  considerable  amount,  the 

spark  timing  will  be  out  very  much.     It   is   quite  possible   to   move   the   cam 

until  the  break  occurs,  when  the  distributing  arm  or  rotor  is  under  the  high 

tension  wire  leading  to  some  other  than  cylinder  No.  1. 


JOB  122.     REMY  IGNITION. 

The  Remy  Battery  Ignition  Units  are  standard  equipment  for  a  large 
number  of  motor  cars.     The  matter  of  care  and  adjustment  is  similar  for  all 

motors.  Where  possible,  the  instruction  book  for 
the  particular  model  being  worked  on  should  be 
consulted. 

Contact  Points. — The  points  should  be  inspected 
regularly  each  1000  miles  to  see  that  they  are  main- 
tained in  good  condition.  If  they  show  signs  of  un- 
even wear  fold  a  strip  of  OO  sandpaper  and  place 
same  between  the  points  in  such  manner  that  the 
sanded  surfaces  are  in  contact  with  the  points.  By 
working  this  forth  and  back  between  the  points  they 
may  be  cleaned  and  any  irregularities  overcome. 

The  points  should  be  maintained  with  a  break 
of  .020"  to  .025".  To  adjust  the  gap  loosen  the 
lock  nut  next  to  the  post  and  turn  the  contact  screw 
until  proper  clearance  or  gap  is  obtained.  Lock 
the  nut  on  the  screw  to  maintain  the  setting. 

Timing   to   the   Engine. — Place    the    piston    in 
cylinder   No.   1  on  top  dead  center.     This  may  be 
accomplished   through   the   aid   of  a   gauge   in   the 
spark  plug  hole  or  by  noting  the  fly  wheel  marking 
whgre  such  is  given.     Work  with  the  piston  on  compression  stroke. 

Place  the  distributor  advance  lever  on  full  retard.  Remove  the  distributor 
cap.  Remove  the  rotor  or  distributing  segment.  This  lifts  up.  Unscrew  and 
remove  the  nut  appearing.  Next  loosen  the  cam  from  the  taper  on  which  it  is 
fitted.  Use  a  screwdriver  to  pry  up  on  it,  rapping  it  lightly  at  the  same  time. 
Use  care  to  prevent  damage  to  any  of  the  parts. 

The  cam  may  now  be  reset  by  moving  it  in  the  direction  in  which  it  rotates 
until  the  points  are  just  opening,  the  engine  being  maintained  in  the  position 
noted  above.     Since  the  spark  occurs  just  as  the  points  separate,  it  will  occur 


Pig.  405.     Remy   Ignition 
Distributor. 


Battery  Ignition 


353 


with  this  setting  at  exact  top  dead 
center.  It  is  safe  to  have  the  piston 
in  cylinder  No.  1  just  a  bit  over  top 
dead  center  on  the  power  stroke  since 
the  spark  control  is  fully  retarded. 

Advancing  the  spark  with  this 
setting  will  give  the  required  range 
for  efficient  engine  operation. 

The  distributor  rotor  may  now  be 
replaced  and  the  distributor  cap  like- 
wise. The  high  tension  cable  leading 
to  cylinder  No.  1  must  be  that  one 
which  attaches  to  the  distributor  cap 
terminal  immediately  over  the  rotor 
within  the  head,  since  it  is  to  that 
terminal  high  tension  spark  will  be 
conducted   when   the  points  break. 

The  other  cables  must  be  led 
from  the  distributor  cap  in  order,  but 


RESISTANCE^ 
UNIT 


HIGH  TENSION 
TERMINAL, 


run  to  the  cylinders  in  their  proper  firing  order 


Fig.  40G.     Kemy  Coil  Assembled. 


WIRES  TO  PRIMARY  WINDING 

WIRE  to  CONDENSEI 


iron:core 


CONDENSER' 


COIL  WINDINGS 


WIRE  FROM 

SECONDARY 

WINDING 


Pig.  407.     Details  of  Remy  Coil  Construction. 


354 


Automotive  Trade  Training 


ROTATING   CONTACT   TO                 ''-J^'~\\ 
TIMER   COVER     POINTS       i            i         /\ 

^H^^9^^^ 

^-- ■■ 

L 

^ 

l;/;^:-     ^  ^^B 

^^,^ 

SECMENT  SPRING   CONTACT       /    ^H^^ 
POINT  TO   TIMER    COVER                           ^^Gi 

m^r 

^f,' 

Fig.    408.     Remy    Chalmers    Timer   with    Distributor    Bloclc   in    Place. 


CONTACT  POINT  LEVfR 

m 

'^ 

te 

POINT  OF  CAM 

^P 

^ 

1 

CONTACT  POINT  GAP    H 

1 

_ __^ 

-/ 

PL 

TIMER   CAM 

CONTAC?     POINT           / 
ADJU:iT>NG  5CPEVV 

^ 

•■ 

^^5^ 

^■1? 

Fig.  409.     Remy   Chalmers   Timer. 

JOB  123.     CONNECTICUT  IGNITION  SYSTEM. 

Connecticut  ignition  apparatus  uses  unrestricted  current  from  the  battery 
for  ignition.  This  insures  a  good  spark  at  all  times  for  use  at  the  plugs.  The 
system  is  able  to  use  this  flow  of  current  without  danger  of  battery  drainage 
or  coil  burning  because  of  its  automatic  switch  arrangement.  A  thermostatic 
device  is  arranged  to  break  the  circuit  in  the  event  that  the  motor  is  stopped 
or  stalled  with  the  ignition  left  on. 

Igniter. — These  are  provided  for  use  on  four,  six,  or  eight-cylinder  engines. 
The  main  constructional  difference  is  the  number  of  cams  milled  on  the  upper 
end  of  shaft  A,  Fig.  412,  which  shows  the  working  parts  of  the  igniter.     Fig. 


Battery  Ignition 


355 


No.   410.     Connecticut   Coil 
and   Igniter. 


Fig.  411.     Section  Con- 
necticut Coil. 


410  shows  an  external  view  of  the  Igniter  and  Coil.     Fig.  411  shows  a  sectional 
view  of  the  Connecticut  coil. 

In  Fig.  412  the  shaft  A  extends  through  the  instrument.  The  lower  end  is 
driven  from  the  engine  at  the  required  speed.  The  cams  B,  milled  on  the  upper 
end,  operate  the  breaker  arm  C  and  point  E  which  it  carries.  G  is  a  roller  on 
which  the  cams  operate  the  arm.  The  point  E  operates  in  conjunction  with 
point  F.  The  spring  H  returns  the  point  E  and  arm  C  to  position  after  the 
cam  passes  the  roller. 


Fig.   412.     Connecticut   Igniter   with   distributor   cap    removed. 


356 


Automotive  Trade  Training 


It  is  during  the  period  of  contact  between  the  points  E  and  F  that  the  coil 
saturation  takes  place.  The  more  complete  the  saturation,  the  better  the 
spark.     The  system  is  designed  to  give  all  the  time  possible  for  this  operation. 

Breaker  Points. — The  breaker  mechanism  of  this  igniter  is  very  easily 
removed  and  replaced.  It  was  so  designed  to  enable  the  user  to  make  a 
complete  replacement  should  there  be  occasion  to  do  so.     It  will  be  found 


Fig.    413. 


MOTOR  RUNNING.  CURRENT  FLOWING. THERMO- 
STATIC ARM  IN  POSITION 


MOTOR  STOPPED, EXPANSION  OCCURRING  IN  THERMO- 
STATIC ARM.WHICH  IS  JUST  ABOUT  TO  RELEASE  PLUNGER. 


Fig.   414.     Connecticut   Automatic    Kick-off 
unit  as  used  witli  Connecticut  switclies. 

advisable  to  replace  the  complete 
breaker  plate  rather  than  individual 
points.  The  successful  operation  of 
the  coil  will  be  hindered  by  any  ir- 
regularities of  the  point  adjustment 
and  in  time  this  may  do  serious  in- 
injury.  Unless  the  points  ir^  prop- 
erly adjusted,  arcing  and  burning  is 
bound  to  occur. 

Automatic  Switch  Feature.  — 
Connecticut  switches  incorporate  an 
automatic  cut-out  feature  in  the 
various  designs.  The  principle  of 
operation  is  the  same  for  the  several 
styles  of  switches.  In  fact,  the  part 
known  as  the  K  unit  is  designed 
into  switches  of  several  dififerent 
types.  The  latest  Connecticut  switch 
is  operated  on  the  toggle  principle. 
In  this  switch,  too,  the  automatic 
device  is  differently  designed,  but  j 
the  principle  is  the  same.  ■ 

To    secure    the    automatic   kick- 
off  of  the  current  in  case  the  engine 
is  left  idle  with  the  ignition   switch   ■ 
on,  a  thermostatic  principle  is  taken  | 


PLUNGER  OFF.  CURRENT  STOPPED-PUSH  IT  BACK 
WHEN  YOU  WANT  TO  START  AGAIN 

Fig.   415.     Connecticut   Automatic 
liick-off  device. 


advantage  of.  One  form  of  the 
device  is  shown  in  Fig.  414,  Another 
form  is  shown  in  Fig.  415.  The 
action  is  as  follows: 


r 


Battery  Ignition 


35? 


As  soon  as  the  motor  stops  running  and  the  interruptions  of  the  ignition 
circuit  cease,  the  flow  of  current  increases  and  heats  up  the  wire  ribbon  about 
the  arm  A,  Fig.  414.  This  arm  is  so  constructed  that  when  heated  it  bends  down 
until  it  makes  contact  with  post  B.  The  current  then  flows  down  post  B 
through  the  wire  which  connects  B  and  C,  up  C  into  the  ribbon  around  D. 
Arm  D  is  constructed  similarly  to  A,  but  is  arranged  to  bend  upward  when 


e^ 


e^ 


I 


BATTETSY 


10 


TQ  CQIU. 


CONOENSER 


REASE  CUP 


Fig.  416.    Connecticut  Switch  and  Igniter  Wiring  Diagram. 

heated.  This  upward  bend  or  movement  releases  the  latch  which  holds  the 
plunger  E  in  the  "On"  position,  causing  it  to  kick  out  and  break  the  ignition 
circuit.     It  requires  a  short  interval  of  time  for  this  action  to  take  place  so 

that  it  does  not  interfere  with 
the  normal  duties  of  the  system, 
but  does  protect  the  battery  and 
coil  when  the  ignition  is  on  and 
the  engine  idle. 

JOB  124.     WAGNER  IGNI- 
TION. 

The  Wagner  ignition  is  de- 
signed to  give  a  hot  spark  for 
low  speeds  and  at  the  same  time 
to  efficiently  take  care  of  the 
maximum  speed  of  which  the 
engine  is  capable.  The  timer 
distributor  and  coil  are  both 
dust  and  waterproof. 

Coil. — The  coil  is  of  the 
non-vibrating  type.  It  is  en- 
closed in  a  hermetically  sealed 
case,  thus  protecting  it  from 
moisture  or  mechanical  injury. 
The  coil  illustrated  in  Fig.  420 
has  a  safety  spark  gap  incorpor- 
ated in  it.  This  gap  serves  to 
protect  the  coil  from  excessive 
electrical  strains  in  event  of 
failure  of  some  other  part  of  the 
high  tension  circuit.  The  action 
of  the  spark  gap  as  the  current 
crosses  it  in  such  a  case  will  be 
noticeable  through  the  mica 
window. 


Fig 


Complete  Wagner   Timer  Distributor. 


358  Automotive  Trade  Training 

The  internal  arrangement  of  the  Wagner  coil  is  different  from  other  coils. 
The  high  tension  current  is  brought  out  in  the  center  at  the  top,  through  a 
bakelite  insulator  which  is  molded  into  the  steel  case.  This  construction 
makes  the  case  very  sturdy.  The  construction  of  the  coil  case  helps  to  prevent 
injury  to  the  windings  and  misfiring  during  wet  weather. 

Distributor  Head. — The  Wagner  timer  distributor  is  shown  in  Fig.  417 
completely  assembled.  The  system  will  operate  over  a  wide  range  of  battery 
voltage.  A  satisfactory  spark  for  ignition  can  be  obtained  even  when  the 
battery  is  too  low  to  crank  the  engine.  Starting  in  this  case  is  effected  by  hand 
cranking.  The  cover  for  the  distributor  is  molded  from  bakelite.  When  the 
high  tension  wires  are  properly  assembled  the  head  is  water-proof. 

Revolving  Distributor. — The  revolving  distributor  carries  the  high  tension 
current  from  the  center  of  the  cover  to  the  terminal  connected  with  the 
cylinder  to  be  fired.  The  metal  plate  carrying  the  current  does  not  make 
actual  contact  with  the  distributing  pins,  but  passes  within  ten-thousandths  of 


Fig.  418.     Setting  cam  on  Wagner  Head. 

an  inch  of  them,  thus  permitting  the  spark  to  jump  to  the  pins  in  the  same 
manner  as  the  spark  jumps  the  plug  gap.  A  special  grade  of  tungsten  is  used 
for  the  contact  points.  It  requires  no  cleaning  or  filing,  and  will  operate  best 
if  left  entirely  alone  until  the  tungsten  is  nearly  worn  away. 

Fitting  New  Contacts. — If  new  contacts  are  necessary,  first  replace  timer 
lever  KC-335  and  contact  screw  KC-313  with  new^  parts.*  Adjust  the  contact 
screw  until  the  points  separate  .020"  to  .025",  after  which  the  screw  is  secured 
by  tightening  the  lock-nut.  Next  note  if  the  points  are  square  with  each 
other  and  touching  over  their  entire  surface.  If  not,  loosen  the  nuts  holding 
the  contact  support.  This  can  then  be  moved  sufficiently  to  line  up  the 
contacts  properly.     Tighten  and  lock  all  nuts. 

The  timing  lever  is  lubricated  by  a  small  wick  contained  in  the  hollow 
spindle  underneath  the  spring  clip.  Three  drops  of  oil  in  this  wick  once  a 
season  is  sufficient.  The  grease  cup  on  the  distributor  shaft  should  have  one- 
half  turn  each  500  miles  of  service. 


*The  marks  KC-335  and  KC-312  appear  stamped  on  new  parts. 


Battery  Ignition 


359 


Setting  the  Ignition. — If  the  timing  of  the  ignition  has  been  disturbed  and 
it  is  necessary  to  reset  it,  this  can  be  accomplished  by  loosening  the  cam  screw, 
the  cam  lightly  on  its  seat,  and  turn  it  in  the  direction  in  which  it  rotates,  until 
then  raising  the  cam  off  its  taper  on  the  shaft  by  prying  it  up  with  a 
screwdriver.     (See    Fig.    418.)     To    reset    the    cam:     First    set    engine    with 


cylinder  No.  1  on  T.  D.  C.  compression  stroke.  Retard  the  spark  fully.  Rest 
the  slot  B  is  opposite  the  timing  lever  C,  and  the  point  of  the  cam  in  line  with 
the  slot  is  just  starting  to  open  the  contacts.  Tap  the  top  of  the  cam  lightly  with 
the  butt  of  the  screwdriver.     This  wili  hold  it  until  the  adjusting  or  clamping 


360 


Automotive  Trade  Training 
might  en  si  01^ 


mStSTANCE 


LOW  TENSION 
TEHMINAL  — 

i(TO  Oe  CONNCCTEO 
TO  S  WITCH) 


SAFETX  6A/> 

WITH 

MICA  WINDOW 


LOWTENSIONI 
ERMINAL 

BE  CON- 
NECTED TO 

TIM  en  lead) 


Fig.  420.     Wagner   Spark  Coil, 
screw  can  be  replaced.     Test  after  tightening  the  cam  screw  to  see  that  the 
setting  has  not  been  changed. 

Wiring  Diagram. — The  wiring  diagram  shown  is  for  the  Elgin  6.  but  may 
be  considered  as  typical  of  the  Wagner  system.  The  student  will  be  interested 
in  tracing  out  the  high  and  low  tension  circuits. 

JOB  125. 
Open  Circuit  in  the  Primary  of  the  Ignition  Coil. — To  test  for  an  open 
circuited  primary,  a  6-volt  battery  is  connected  to  the  terminals  of  the  primary 


Fig.  421. 


Battery  Ignition 


361 


winding  of  the  coil  with  the  ammeter  in  series  as  shown  in  Fig,  421.  In  most 
coils  the  current  flow  will  be  about  ten  amperes  if  the  winding  is  in  good 
condition.  (Consult  the  coil  manufacturer  to  find  out  the  actual  value  or  try- 
out  several  coils  known  to  be  good.) 

Refer  to  Chapter  14,  Job  160,  for  instruction  on  the  use  of  the  Fault  Finder 
Test  Set. 


Fig.  422. 
JOB  126. 
Open  Circuit  in  the  Secondary  of  the  Ignition  Coil. — To  test  for  an  open 
circuited  secondary,  connect  the  thirty-volt  range  of  the  instrument  in  series 
with  the  battery  and  the  secondary  winding  of  the  coil  as  shown  in  Fig.  422. 
An  open  circuit  will  be  indicated  when  the  reading  is  zero. 
For  a  good  winding  the  reading  will  be  about  three  volts. 


FR/MA/ey 


mi^ 


Fig.   423. 
JOB  127. 
Open  Circuit  in  Ignition  Coils  vdth  Connected  Windings. — In  some  coils 
the  primary  and  secondary  windings  are  connected  together  with  the  coil  as 


362 


Automotive  Trade  Training 


shown  in  Fig.  423.  When  this  is  the  case  the  test  can  be  made  on  the 
secondary,  as  shown  by  the  full  line  connection,  and  on  the  primary  by  chang- 
ing the  connection  as  indicated  by  the  dotted  line.  The  thirty-volt  range  is 
used.     Zero  reading  in  either  case  indicates  an  open  circuit. 

JOB  128. 

Short  Circuit  in  the  Primary  of  the  Ignition  Coil. — To  determme  if  the 
primary  winding  is  short  circuited,  connect  the  ammeter  in  series  with  the 
windinsf  and  the  battery  as  shown  in  Fig.  421,  Job  125.  A  short  circuited 
winding  will  be  indicated  by  a  reading  on  the  ammeter  in  excess  of  the  normal 
current  for  a  good  coil.  (Consult  a  coil  manufacturer  for  the  normal  value  of 
a  current.) 


Fig.   424. 
JOB  129. 

Short  Circuit  in  the  Secondary  Winding  of  the  Ignition  Coil. — Connect  the 
thirty-volt  range  as  in  Job  126,  Fig.  422. 

A  completely  short  circuited  coil  is  denoted  by  the  voltmeter  indicating 


C0N0£A/5£e 


^ ^>'^^ 


Fig.  425. 


Battery  Ignition 


363 


the  battery  voltage.     Partial  short  circuit  will  result  in  a  value  less  than  the 
battery  voltage  but  somewhat  higher  than  three  volts. 

JOB  130. 

Ground  Between  Primary  and  Secondary  Windings. — Connect  the  battery 
and  the  thirty-volt  range  of  the  instrument,  as  shown  in  Fig.  424,  to  one  end 
of  the  primary  and  one  end  of  the  secondary  windings.  If  the  coils  are 
grounded  on  one  another  an  indication  will  be  obtained. 

Note: — This  test  cannot  be  performed  on  coils  having  internally  connected 
windings. 

JOB  131. 

Grounded  Condenser. — Connect  a  six-volt  battery  and  the  thirty-voIt  range 
of  the  instrument  in  series  as  shown  in  Fig.  425.  Connection  is  made  to  only 
one  terminal  of  the  condenser,  the  circuit  being  completed  through  the  metal 
case  of  the  condenser.  If  the  condenser  plates  under  test  are  grounded  to  the 
case,  an  indication  will  be  obtained.  No  indication  denotes  absence  of  a 
ground. 

Change  the  connection  from  terminal  No.  1  to  terminal  No.  2  and  repeat 
the  test  on  the  other  set  of  plates. 

JOB  132. 

Short  Circuited  Condenser. — Connect  a  six-volt  battery  and  the  thirty-volt 
range  of  the  instrument  in  series  to  the  terminals  of  the  condenser.     Fig.  426. 

No  indication  will  be  obtained  if  the  condenser  is  good.  If  short  circuited, 
an  indication  will  be  obtained. 

C0ND€/^5Eie 


Fig.  426. 


CHAPTER  13 

MAGNETO  IGNITION 

This  type  of  automotive  ignition  is  divided  into  tv^o  general 
classes.  These  are  low  tension  magneto  and  high  tension  magneto. 
Low  tension,  being  the  most  closely  connected  to  battery  ignition, 
will  be  described  first.  Much  of  the  matter  given  with  relation  to 
the  low  tension  is  applicable  to  the  high  tension  magneto.  Low  ten- 
sion magnetos,  excepting  the  type  used  on  the  Ford  car,  are  con- 
sidered obsolete  for  automobile  use. 


FiJ,^    427.     Electrical    system    on    I'ackard    truck. 

Low  Tension  Magneto. — By  a  low  tension  magneto  is  meant  a 
machine  generating  current  in  a  mechanical  manner,  but  of  insuffi- 
cient pressure,  or  voltage,  to  cause  it  to  jump  air  gaps  on  spark  plugs. 
The  machine  is  used  to  produce  the  current,  while  coils  are  used  to 
step  it  up  to  a  high  tension  point  where  it  will  jump  the  plug  points. 

The  voltage  of  the  low  tension  magneto  is  about  six  volts  in  most 
cases.  The  Ford  magneto  generates  about  eighteen  volts.  Magnetos 
generate  A.  C.  current  only.  The  action  of  coils  is  not  materially 
influenced  by  this  fact  since  the  magneto  is  usually  timed  so  that  the 
one-current  impulse  as  generated  in  one-half  revolution  is  used  to 
produce  the  spark  in  each  cylinder.  While  the  current  does  reverse 
in  the  armature  and  consequently  within  the  coil,  it  does  not  alternate 
in  producing  any  one  spark.  It  is  rather  only  in  the  direction  in 
which  the  separate  or  successive  sparks  flow  that  there  is  reversal 

364 


Magneto  Ignition  365 

of  direction.  In  other  words  one  spark  will  follow  the  high  tension 
wire  to  the  plug  and  return  to  the  coil  through  the  engine  frame,  the 
next  due  to  the  reversal  of  direction  within  the  magneto  will  go 
through  the  ground  to  its  plug  and  return  to  the  coil  through  the 
wire. 

To  illustrate  more  fully.  When  A.  C.  current  is  used  to  light  the 
bulbs  in  house  lighting,  the  direction  of  flow  of  the  current  through 
the  filament  reverses  a  number  of  times  per  second.  Although  an 
A.  C.  machine  is  used  to  generate  the  current  which  is  stepped  up 
and  used  to  ignite  the  fuel  charge  within  the  cylinder,  it  flows  in  only 
une  way  since  only  one  wave  is  used  to  produce  any  one  spark.  Each 
succeeding  wave,  although  in  different  or  alternate  directions,  is  used 
to  produce  one  spark  and  ignite  one  and  a  separate  charge.  The 
current  waves  do  not  alternate  back  and  forth  in  producing  the  spark 
in  any  one  cylinder  where  the  shuttle  or  H  type  armature  is  used. 

H  or  Shuttle  Type  Low  Tension  Magneto. — Where  this  type  of 
armature  is  used  for  low  tension  magneto  work  there  is  but  one 
winding  on  the  armature.  In  constructing  the  magneto  the  usual 
design  is  to  mount  the  armature  between  two  pole  shoes  on  the  out- 
side of  which  are  bolted  or  screwed  the  permanent  magnets.  The 
permanent  magnets  are  used  to  produce  the  magnetic  flux  or  field. 
Brass  or  bronze  bearing  supports  are  mounted  across  the  ends  of  the 
pole  shoes  to  carry  the  armature.  Thus  the  armature  is  rotated  on 
its  bearings  within  the  magnetic  field,  cutting  the  lines  of  force  or 
magnetic  flux,  and  taking  off  through  its  windings  the  primary  cur- 
rent thereby  induced. 

Inductor  or  Stationary  Coil  Type. — In  this  type  of  magneto  the 
coil  or  winding  is  made  to  remain  stationary,  while  the  magnetic  flux 
IS  made  to  cut  the  winding  either  through  a  rotating  inductor  or  a 
rotating  field.  These  points  are  brought  out  more  fully  when  the 
various  types  are  considered. 

Magnets. — The  nature  of  magnets  as  well  as  the  methods  of  con- 
structing, charging,  and  caring  for  them  was  described  in  Chapter  10. 
In  the  practical  application  of  magnets  to  the  magneto  certain  forms 
are  standard.  In  lighter  magnetos  either  a  wide  single  magnet  is 
used,  or  two  lighter  ones  side  by  side.  In  heavier  machines  where 
more  is  demanded  of  them  the  magnets  may  be  made  to  fit  one  over 
the  other,  and  as  many  as  four,  six,  or  nine  are  used  in  a  group. 
Whatever  the  number  used,  the  purpose  served  being  the  same  in  all 
cases,  they  maintain  a  permanent  magnetic  field  from  which  may  be 
induced  a  primary  circuit  to  feed  the  coil  and  produce  a  jump  spark. 

Pole  Shoes. — In  the  nature  of  the  magnets  the  lines  of  force  are 
stronger  at  or  near  the  ends  than  elsewhere.  To  facilitate  this  flow 
of  the  lines  of  force  and  to  insure  a  proper  field  of  magnetic  flux  for 
the  armature  to  turn  in,  much  attention  is  given  the  design  of  the 


366  Automotive  Trade  Training 

pole  shoes.  Each  manufacturer  gives  special  attention  to  this  and 
the  slight  differences  will  be  evident  in  the  illustrations  and  in  the 
models  the  student  comes  into  contact  with. 

Aside  from  the  special  magnetic  duty  which  they  perform,  the 
pole  shoes  are  used  very  often  to  build  up  the  other  units  of  the 
machine.  To  them  are  fastened  the  magnets,  the  bearing  supports, 
dust  covers,  and  base. 

Non-Magnetic  Metals. — Owing  to  the  fact  that  the  magneto  must 
be  very  compact  and  carefully  enclosed  to  exclude  all  dust,  dirt, 
grease,  etc.,  as  well  as  the  fact  that  it  is  usually  mounted  directly  on 
the  engine,  care  must  be  used  in  its  mounting  and  construction  to 


Fig,  428.    Eisemann  High  Tension  Magneto. 

prevent  any  disturbance  of  the  magnetic  field.  By  this  is  meant  that 
nothing  must  be  allowed  to  come  in  contact  with  the  magneto  which 
will  divert  the  flow  of  the  flux  from  the  north  pole  to  the  south  pole 
of  the  field.  For  this  reason  the  base,  bearing  supports,  armature 
ends,  and  certain  other  parts  are  made  from  non-magnetic  metals 
such  as  bronze,  brass  or  aluminum.  In  some  cases  screws  of  brass 
are  used,  and  where  this  is  the  case  iron  should  never  be  substituted. 
By  non-magnetic  metals  are  meant  those  not  attracted  by  the  mag- 
netic lines  of  force  as  are  iron  or  steel.  To  avoid  troubles  hard  to 
locate,  use  extreme  care  in  rebuilding  a  magneto. 

Armature. — The  armature  of  the  H  or  shuttle  type  shown  in 
Fig.  484  and  elsewhere  is  commonly  used  in  both  low  and  high  ten- 
sion magnetos.  No  shaft  runs  through  it.  As  mentioned  before, 
non-magnetic  metals  are  used  to  hold  the  ends  of  the  armature 
together  and  to  support  the  stub  shafts  on  which  the  armature  turns. 


Magneto  Ignition 


367 


Bearings  are  usually  ball  bearings.  The  magneto  must  be  very  care- 
fully assembled  since  very  slight  clearance  is  allowed  between  the 
armature  and  the  pole  shoes.  Sometimes  the  apprentice  will  allow 
the  screws  used  for  holding  the  parts  together  to  become  mixed,  with 
the  result  that  the  ones  which  are  a  bit  too  long  may  project  through 
the  pole  shoes  and  damage  the  armature. 

Slip  Rings. — The  nature  and  purpose  of  the  slip  ring  was  pre- 
viously explained.  One  or  two  may  be  used  on  the  magneto.  If  only 
one  is  used  the  one  end  of  the  primary  winding  is  led  to  it  and 
fastened  in  direct  contact.  On  this  slip  ring  a  carbon  brush  rides  and 
carries  the  current  to  the  external  circuit.  The  other  end  of  the 
primary  winding  is  grounded  through  the  shaft  and  bearings,  or  some 
special  form  of  ground  connection  may  be  used.     This  furnishes  the 


Fig.   429.     Magneto   Firing   Order-  1-2-4-3. 

Other  connection  to  the  external  circuit.  Where  two  slip  rings  are 
used  one  is  provided  at  each  end  of  the  armature.  The  current  may 
be  taken  ofif  direct,  but  the  one  on  the  rear  of  the  armature  is  fre- 
quently grounded  through  a  small  carbon  brush  in  the  dust  cover, 
or  within  the  base.  Sometimes  the  end  within  the  magneto  is 
grounded  through  a  brush  onto  the  bearing  support.  This  takes  the 
place  of  a  slip  ring.  In  the  case  of  the  low  tension  magneto  the  slip 
rings  conduct  only  low  tension  current  as  there  is  no  high  tension 
current  within  the  armature  winding. 

Breaker  Points. — In  magnetos  of  the  shuttle  armature  type  the 
machine  must  be  driven  in  fixed  relation  to  the  engine  speed.  In  a 
magneto  for  a  four-cylinder  engine  the  armature  turns  at  crank  shaft 
speed  that  is  one  to  one.  If  the  engine  is  a  six-cylinder  one,  then 
the  armature  turns  at  one  and  one-half  crank  shaft  speed  or  one  and 
one-half  to  one.  This  the  student  will  note  provides  for  one-half  of 
one  revolution  for  each  cylinder  fired.  This  is  absolutely  essential  as 
two  sparks  are  available  for  each  revolution  of  the  armature.     In 


368  Automotive  Trade  Training 

other  words,  the  machine  is  so  designed  that  at  two  points  in  each 
revolution  of  the  armature  the  maximum  number  of  Hues  of  force  is 
being  cut  by  the  armature  windings.  When  this  condition  is  present 
the  current  wave  is  said  to  be  at  its  peak,  and  this  is  the  time  to  open 
the  contact  points.  When  the  current  wave  is  at  its  peak  the  mag- 
netism of  the  coil  will  be  at  its  maximum,  and  as  the  points  open 
there  is  the  maximum  break  of  magnetic  lines  of  force,  and  conse- 
quently the  maximum  intensity  of  high  tension  spark  at  the  plug 
points.  This  means  that  as  the  points  open  the  armature  would  be 
close  to  the  position  shown  in  Fig.  449.  A  retard  and  advance  range 
of  about  35  degrees  is  available  with  this  type  armature.  That  is, 
the  peak  of  the  current  wave  is  great  enough  or  long  enough  to 
permit  of  advancing  or  retarding  the  opening  of  the  points  within  the 
range  mentioned,  and  still  have  sufficient  voltage  to  produce  a  spark 
at  the  plug  by  aid  of  the  step-up  or  transformer  coil.  Periods  of  no, 
cr  zero,  current  are  reached  twice  during  each  revolution.  At  this 
point  the  direction  of  current  is  reversed. 

Transformer  or  Step-Up  Coils. — Several  distinct  methods  of  step- 
ping up  the  current  in  the  external  circuit  are  in  use.  Each  requires 
the  use  of  an  ignition  coil,  or  in  other  words,  a  transformer  coil  to 
transform  the  current  from  low  to  high  tension.  The  difference  in 
the  two  systems  is  the  position  occupied  by  the  contact  point. 

Contact  Points  in  Series. — By  this  is  meant  that  the  breaker  or 
contact  points  are  connected  in  series  with  the  armature  winding  and 
the  primary  winding  of  the  step-up  coil.  In  other  words,  the  arma- 
ture takes  the  place  of  the  battery  as  the  source  of  current,  and, the 
action  is  exactly  similar  to  the  standard  battery  system.  The  current 
generated  by  the  magneto  flows  into  the  primary  coil  of  the  trans- 
former, thence  back  again  to  the  armature.  The  contact  points,  being- 
closed,  permit  this  flow.  When  opened  they  check  or  stop  this  flow. 
This  causes  the  lines  of  force  about  the  coil  to  drop  back  to  the  core. 
The  collapse  and  quick  return  of  these  lines  of  force  is  insured  by  the 
condenser  action.  The  induced  current  within  the  secondary  coil,  due 
to  the  rapidly  falling  lines  of  force,  is  high  and  is  used  to  jump  the 
plug  points.  It  will  be  seen  that  the  induction  is  dependent  on  the 
rapidly  collapsing  lines  of  force.  The  second  method  is  exactly  the 
reverse  in  action.  Rapidly  built  up  or  out-going  lines  of  force  are 
depended  on  in  this  case  for  high  tension  induction. 

Shunt  Current  Interruption  Induction. — The  same  coil  and  low 
tension  magneto  with  condenser  and  interrupter  is  used.  However, 
instead  of  taking  the  current  from  the  magneto  armature  where  it  is 
generated  through  the  primary  winding  of  the  coil  and  then  back  to 
the  magneto,  it  is  led  through  a  shunt  and  directly  back  to  the  arma- 
ture through  the  magneto  points  which  are  closed  at  this  time.  This 
insures  a  high  pressure  being  built  up  within  the  magneto  armature. 


Magneto  Ignition 


369 


When  the  armature  is  in  a  vertical  position,  or  position  of  greatest 
voltage,  the  interrupter  points  are  opened.  The  condenser  is  across 
the  points  so  that  it  is  charged  instantly,  but  the  primary  circuit  of 
the  coil  is  also  across  the  points  so  that  it  affords  a  second  path  of 
travel  for  the  current  being  generated.  Since,  however,  the  shunt 
affords  an  easier  path,  little  will  flow  to  the  coil  until  the  points 
separate. 

When  the  points  separate,  the  condenser  is  charged  at  the  same 
time  that  current  from  the  armature  surges  through  the  primary  wind- 
ing of  the  coil.  The  discharge  of  the  condenser  aids  the  current  surg- 
ing through  the  coil  from  the  armature,  and  both  together  produce 


Fig.   430.     Method    of   Wiring   in   a    Switch. 

such  a  rapid  or  instantaneous  building  up  of  magnetism  that  the 
rising  or  outgoing  lines  of  force  cut  the  secondary  coil  with  such 
rapidity  and  in  such  numbers  that  a  spark  is  available  from  the  in- 
duced current,  to  ignite  the  charge  within  the  cylinder.  The  student 
has  seen  that  this  is  the  exact  reverse  from  the  method  used  in  the 
battery  and  in  the  other  method  of  utilizing  the  low  tension  magneto, 
in  that  the  induction  of  secondary  current  takes  place  on  magnetizing 
the  coil  rather  than  on  demagnetizing  it.  After  the  first  spark  is 
delivered  and  the  points  have  closed  again,  the  armature  will  start 
building  up  for  the  next  spark  which  will  occur  as  the  points  are 
opened  after  one-half  revolution  from  the  point  of  first  break  and 
spark.  Each  half  revolution  a  spark  is  delivered  to  the  engine.  Two 
of  these  sparks  are  from  the  action  of  one  of  the  breaker  lobes,  the 
other  two  from  the  other  lobe.     Sometimes  a  car  having  magneto 


370 


AuTOMOTufi  Trade  Training 


ignition  seems  to  "hit"  better  on  two  cylinders  than  on  the  other  two. 
This  can  often  be  traced  to  imperfect  breaker  lobes  or  cams. 

Distributing  High  Tension  Current  from  a  Low  Tension  Mag- 
neto.—The  current  is  generated  within  the  magneto,  is  taken  out  of 
it  to  the  transformer  coil  where  it  is  stepped  up  through  the  induc- 
tion method  from  about  six  volts  to  fifteen  or  twenty  thousand,  when 
it  is  returned  to  the  magneto  to  be  distributed  to  the  proper  cylinder 
on  the  engine.  It  enters  the  center  of  the  magneto  distributor  on  a 
high  tension  wire,  and  then  is  carried  to  the  proper  contact  within  the 
distributor  cover  by  the  distributor  brush.     The  distributor  on  the 


CoJitroi  Bus' 


nk  IMug 


d  Wife 


Magnf-to 


Fig.   iol.     Magneto   Installation. 

magneto  is  similar  in  action  to  the  distributor  head  for  battery  igni- 
tion. Sparks  are  distributed  to  each  segment  in  turn,  but  the  wires 
running  from  the  segments  must  be  carried  to  the  proper  cylinders 
to  give  correct  firing  order. 

Timing  Spark  on  Low  Tension  Magnetos. — It  has  been  shown 
that  the  magneto  armature  of  the  H  type  runs  at  a  fixed  speed  rela- 
tion with  reference  to  the  engine  crank  shaft.  The  one  to  one  rela- 
tion for  the  four-cylinder  engine  is  used  here  for  an  illustration.  Two 
sparks  are  generated  each  revolution,  four  sparks  are  produced  in 
two  revolutions.  Four  sparks  are  needed  to  fire  the  four  cylinders  of 
the  engine  in  two  revolutions.  Driving  the  armature  of  the  magneto 
at  crank  shaft  speed  cares  for  the  proper  number  of  sparks  but  pro- 
vides no  speed  fitted  to  distribute  them  to  the  cylinders  at  correct 
time.     Accordingly  a  gear  is  fitted  onto  the  armature  or  armature 


Magneto  Ignition  371 

shaft  which  drives  another  gear  carrying  or  turning  the  distributor 
brush.  The  gear  ratio  is  two  to  one.  The  armature  gear  is  smaller 
and  turns  twice  while  the  distributor  gear  turns  once.  The  desired 
result  of  distributing  the  four  sparks  to  the  four  cylinders  is  thus 
secured. 

For  a  six  cylinder  the  distributor  brush  is  slowed  down  to  turn 
once  to  three  turns  of  the  armature,  but  the  armature  is  driven  at 
one  and  one-half  crank  shaft  speed  so  that  the  distributor  gear  and 
brush  still  travel  one  turn  to  two  of  the  crank  shaft.  However,  six 
sparks  are  produced  and  delivered  in  two  turns  of  the  crank  shaft, 
thus  firing  all  cylinders.  This  is  the  working  out  of  the  ignition  for 
the  four-cycle  engine  no  matter  how  many  cylinders.  This  was  ex- 
plained in  Chapter  7.  If  a  magneto  is  removed  from  the  engine  it 
may  be  replaced  on  the  engine  out  of  time.  Care  should  be  used  to 
observe  proper  markings  and  timing  of  valves  with  reference  to  com- 
pression strokes.  Magnetos  dismantled  may  have  their  internal  tim- 
ing disturbed  unless  due  care  is  used.  These  matters  are  treated  in 
detail  elsewhere. 

Dual  Ignition. — By  dual  ignition  is  meant  not  double,  but  rather 
two  kinds  of  ignition  using  the  same  set  of  plugs,  spark  plug  wires, 
and  distributor  units.  In  connection  with  the  low  tension  magneto, 
dry  cells  are  used  as  the  source  of  current  supply  for  starting,  after 
which  the  switch  is  thrown  in  such  position  as  to  permit  of  operating 
the  engine  on  the  current  generated  by  the  magneto.  A  storage 
battery  may  be  used  in  lieu  of  dry  cells. 

Dual  Ignition  Switch. — The  switch  for  the  dual  system  is 
arranged  to  substitute  the  battery  as  the  source  of  current  supply 
for  the  magneto,  and  vice  versa.  One  throw  of  the  switch  performs 
the  operation  of  cutting  out  one  source  of  supply  and  cutting  in  the 
other,  thus  making  the  operation  of  starting  on  battery  current  and 
running  on  the  magneto  practicable.  If  the  change  is  not  quickly 
made  the  engine  will  stop. 

Push  Button  Starting. — Where  dual  ignition  is  used  it  is  general 
practice  to  place  a  push  button  in  the  switch.  This  push  button  may 
be  made  to  take  the  place  of  the  interrupter  or  contact  points.  Vibrat- 
ing the  push  button  with  the  fingers  causes  a  spark  to  be  produced 
within  the  cylinder  on  compression.  If  a  fuel  charge  properly  com- 
pressed is  present  the  engine  will  start  when  this  spark  occurs.  The 
uncertainty  of  the  engine  stopping  with  a  cylinder  ready  to  be  fired 
makes  the  system  an  uncertain  proposition.  Along  with  the  other 
parts  of  the  low  tension  magneto  this,  while  still  found,  is  considered 
obsolete. 

Low  Frequency  Inductor  Type  Magnetos. — In  the  low  frequency 
inductor  type  the  magnets  and  pole  shoes  constituting  the  field  are 
very  similar  to  the  armature  type.    However,  instead  of  the  armature 


372  Automotive  Trade  Training 

with  its  slip  rings  and  revolving  winding,  an  inductor  of  the  nature  of 
that  shown  in  Fig.  441  is  used  to  carry  the  flux  through  a  stationary 
coil.  The  -inductors  are  so  designed  that  in  certain  positions  they 
act  as  a  bridge' to  carry  or  conduct  the  magnetic  flux  from  the  north 
pole  to  the  south  pole.  However,  the  inductors  are  so  made  and 
mounted  that  a  coil  rests  between  them  over  the  shaft.  When  the 
magnetic  flux  flows  through  the  inductors,  it  is  made  to  cut  the  wind- 
ings of  this  coil.  The  more  flux  flowing  through  the  inductors  and 
coil  the  more  current  induced.  As  in  the  other  type,  there  are  zero 
points  to  the  current.  The  current  is  alternating.  The  current  waves 
reach  a  peak  and  it  is  at  this  peak  or  as  near  the  peak  as  practicable 
that  the  points  must  be  set  to  break.  The  current  is  a  pulsating 
A.  C.  current  for  the  following  reason.  On  one  position  the  flux 
flows  from  the  north  pole  through  the  one  inductor,  through  the  coil, 
through  the  other  inductor,  and  then  into  the  south  pole.  With  the 
next  half  revolution  of  the  inductor  the  other  inductor  arm  is  at  the 
north  pole.  Consequently  in  this  case  the  flux  flows  into  this  one 
through  the  coil  and  out  of  the  other  one.  The  flux  has  cut  the  coil 
windings  first  in  one  direction  then  in  the  reverse  direction.  The 
current  induced,  as  previously  explained  in  Chapter  10,  bears  a  definite 
relation  to  the  direction  in  which  the  flux  cuts  the  coil  or  the  coil 
cuts  the  flux. 

No  Brushes. — Since  the  winding  is  stationary,  there  is  no  need 
.  cf  making  any  provision  for  slip  rings  or  brushes  in  this  type  of 
magneto.  The  ends  are  either  both  led  to  terminals,  or  one  grounded 
and  the  other  provided  with  a  suitable  terminal.  As  the  current  is 
taken  off  it  is  A.  C.  current,  but  here  again  the  machine  is  run  in 
fixed  relation  to  the  engine.  Only  one  current  wave  or  pulsation  and 
only  the  peak  of  that  is  used  to  produce  a  spark.  As  previously 
explained,  each  of  these  waves  in  turn  is  carried  to  the  step-up 
transformer  and  used  to  induce  the  high  tension  jump  spark  current 
which  is  led  along  one  wire  to  the  plug  for  a  certain  cylinder.  While 
the  output  of  the  machine  is  A.  C.  current,  the  single  wave  used  for 
any  one  spark  as  well  as  the  induced  current  is  D.  C.  current.  There 
IS  in  reality  no  difference  in  the  action  of  this  type  of  magneto  and 
that  of  the  shuttle  or  H  armature  type,  excepting  only  in  the  manner 
in  which  the  flux  cuts  the  coil  windings  to  produce  the  low  tension 
current.  Each  is  provided  with  breaker  points  or  interrupter  for 
breaking  the  low  tension  current,  and  a  distributor  for  distributing  the 
high  tension  current  to  the  plugs  as  it  is  brought  from  the  trans- 
former coil  where  it  has  been  stepped  up.  One  advantage  of  the 
inductor  type  is  that  the  current  will  raise  to  a  peak  and  hold  that 
value  for  some  little  time  before  it  drops  back  toward  zero  value. 

The  armature  type,  having  reached  maximum  potential  or  value, 
starts  dropping  down  immediately.    The  result  is  that  the  armature 


Magneto  Ignition 


373 


type  will  not  give  quite  as  hot  a  spark  on  retard  as  it  will  on  ad- 
vance, while  the  inductor  type  will,  approximately  the  same  value  of 
current  being  available  for  the  entire  range.  Being  a  low  frequency 
machine  the  inductor  type  must  be  driven  as  is  the  armature  type  at 
a  fixed  speed  relation  with  the  crank  shaft.  That  is  a  one  to  one 
ratio  for  a  four-cylinder  engine. 

High  Frequency  Inductor  Type  Magnetos. — These  may  be  on 
the  general  principle  of  the  above  if  more  inductors  are  added.  The 
Ford  magneto  is  of  the  high  frequency  inductor  type.  With  the 
armature  type  or  low  frequency  type  the  current  waves  must  be 
timed  with  the  engine  speed.  This  is  necessary  to  insure  the  peak 
of  a  current  wave  available  at  the  proper  time.     This  does  not  apply 


Fig-.  432.     Typical  Magneto  Wiring-  Diagram.     (Wired  without  reference  to  firing  order.) 

to  the  Ford  Magneto  since  there  are  sixteen  pulsations  or  waves  of 
current  for  each  revolution  of  the  magneto,  which  is  built  into  the 
flywheel  and  necessarily  rotates  at  engine  speed.  Taking  this  into 
consideration,  the  frequency  of  the  waves  is  so  high  that  current  may 
be  said  to  flow  at  all  times. 

Accordingly,  in  timing  the  engine  it  is  not  necessary  to  make 
allowance  to  have  the  spark  occur  at  the  peak  of  the  current  wave, 
as  this  point  is  arrived  at  so  frequently  that  it  would  be  difficult  to 
find  a  point  on  the  timer  contact  when  the  spark  would  be  delayed 
more  than  a  few  degrees  due  to  the  lack  of  a  high  enough  pressure 
or  current.  It  is  a  matter  of  fact,  however,  that  there  may  be  a  little 
variation  of  the  timing  of  the  spark  due  to  the  lack  of  a  sufficiently 
high  voltage  from  the  generator  or  magneto.  The  spark  may  occur 
a  few  degrees  early  or  a  few  degrees  late. 

Method  of  Generating. — Current  is  generated  or  induced  to  flow 
in  the  armature,  or  the  inductor  of  the  machine,  by  the  field  of  perma- 


374 


Automotive  Trade  Training 


SEARCHLIGHT 


DASHtt-OeTTEO 
LINE  INDICATES 
LIGHTING  CmCUITA 


DOTTED  LINES  INDICATE 
BATTERIES   WHICH  ARE 
NOT  fJECESSA/fr. 
CONNECT  AS    SHOWH 
IF  USED. 


GROUND  TO 
ENGINE  FRAME. 

Fig.  433.    K  W   Inductor  Type   Low   Tension  Magneto   witli  Ignition  and   Liglit  in 
Circuit.     Battery    Current   for    Starting. 

nent  magnets  rotating  in  front  of  it  and  in  close  proximity  to  it.  One 
thirty-second  of  an  inch  is  allowed  as  clearance  between  the  two. 
With  sixteen  magnets  mounted  with  their  like  poles  together,  cut- 
ting past  the  sixteen  inductor  coils,  it  is  seen  that  when  the  two  north 
poles  of  a  group  are  over  the  core  of  an  inductor  the  flux  will  enter 
it  and  flow  to  the  core  of  an  adjacent  inductor  coil,  from  which  it  will 


Magneto  Coil  Spool 


Copper  Wire 

End  of  Ribbon   1 
Grounded  Here  J 

To  Coil 

Magneto  Coil  Support 


Magnet 
Flywheel 

Magnet  Clamp 


Ford   Magneto. 

emerge  to  enter  the  south  poles  over  it.     This  flow  of  the  magnetic 
lines  of  force  or  flux  induces  a  wave  of  current  within  the  coils  of  the 


i 


Magneto  Ignition 


375 


inductors.  Simultaneously  with  this  action  the  same  process  is  going 
on  in  seven  other  sets  or  groups  of  magnets  and  inductors.  However, 
when  the  two  north  poles  have  advanced  to  the  inductor  over  which 
the  south  pole  stood,  the  magnetic  flux  flows  into  its  core  where  it 
previously  came  out.  This  results,  of  course,  in  an  alteration  of  the 
direction  of  flow  and  the  second  pulse  of  current  is  in  the  reverse 
direction  through  the  inductor  coils.  When  the  next  inductor  is 
reached  the  direction  of  flow  is  again  changed,  and  so  on  all  the  way 
around  the  inductors  of  which  there  are  sixteen  mounted  on  the  one 
magneto  coil  assembly  frame.     Sixteen  times  in  one  revolution  the 


Fig.   435.     Section    High    Tension   Magneto. 

direction  of  current  is  changed,  because  of  a  reversal  of  polarity  in 
the  inductors.  Eight  waves  flow  from  the  magneto  into  the  external 
circuit  in  one  direction,  and  eight  others  in  the  reverse  direction. 
These  waves  follow  each  other  so  closely  that  there  is  a  current  flow 
even  enough  to  be  used  for  lighting  as  well  as  for  the  vibrating  coils. 
External  Circuit  on  Ford  Ignition. — One  terminal  of  the  low  ten- 
sion armature  is  grounded.  The  other  is  connected  with  the  terminal 
mounted  on  the  center  of  the  top  of  the  transmission  cover  case. 
Between  this  terminal  and  the  ground  or  metallic  parts  of  the  car,  all 
electrical  units  using  the  low  tension  current  must  be  arranged.  As 
described  under  battery  ignition,  the  Ford  ignition  system  brings  the 
low  tension  current  to  the  timer  roller  and  from  there  to  the  timer 
segments  as  it  rolls  over  them,  then  to  the  separate  vibrating  coils 
connected  to  the  timer  segments  or  contacts.     The  contacts  within 


376 


Automotive  Trade  Training 


the  coil  box  are  connected  to  the  magneto  terminal  which  completes 
the  external  circuit  with  reference  to  ignition.  The  coil  box  switch 
naturally  must  be  considered  as  being  placed  in  the  circuit  to  open 
and  close  it,  otherwise  the  engine  might  be  cranked  at  any  time  with 
reference  to  the  spark  and  would  have  to  be  choked  to  stop  it. 

The  distribution  of  the  high  tension  current  was  explained  under 
the  battery  ignition.  It  is  well  to  have  in  mind  the  fact  that  instead 
of  one  coil  four  are  used,  doing  away  with  the  necessity  of  distributing 
the  high  tension  current  through  a  special  distributor.  Any  plug 
will  receive  a  spark  only  when  its  respective  coil  is  vibrating  and 
the  coil  vibrates  only  when  its  respective  segment  in  the  timer  is  in 
contact  with  the  rollers,  and  this  roller  can  only  be  in  contact  with 
that  segment  when  the  cylinder  to  receive  the  spark  is  on  the  finish 
of  the  compression  stroke. 

The  only  other  type  of  high  frequency  magneto  is  the  one  having 
the  drum  armature  wound  with  a  number  of  coils.  This  type  may  be 
used  for  lighting  lamps,  but  not  for  charging  a  storage  battery  since 
only  D.  C.  current  may  be  used  for  this. 


HIGH  TENSION  MAGNETOS 

High  tension  magnetos  are  so  called  because  the  machine  is  com- 
plete within  itself,  and  is  able  to  deliver  a  high  tension  jump  spark  to 
the  plugs  without  the  aid  of  any  outside  help.  No  transformer  coil 
of  any  nature,  and  no  external  units  whatever  are  required. 


Fig.  436.  Typical  Magneto  Construction. 

All  units  for  ignition  either  low  tension  or  battery  are  still 
required,  but  all  are  built  into  the  magneto  itself.  The  manner  of 
building  in  the  high  tension  coil  condenser  distributor,  etc.,  is  of 
interest  to  the  student. 

High  Tension  Armature  Type. — In  this  machine  the  arrange- 
ment of  magnets,  pole  pieces,  frame  and  general  design  are  very 


Magneto  Ignition 


377 


similar  to  the  low  tension  of  the  same  type.  The  main  difference  in 
principle  of  operation  is  the  addition  of  the  secondary  or  high  tension 
coil  over  the  primary  or  low  tension  coil  on  the  armature.  Other 
necessary  units  are  also  built  in  so  as  to  make  it  self-contained. 

Low  Tension  Circuit  in  Armature  type. — In  the  high  tension 
magneto  the  low  tension  or  primary  current  is  generated  just  as  in 
the  armature  type  low  tension  magneto.  Not  as  many  turns  of  wire 
are  used  due  to  lack  of  space  on  the  armature.  Two  waves  of  cur- 
rent are  generated  again,  one  for  each  half  revolution.  These  again 
are  alternating.     Just  as  the  peak  of  the  current  wave  is  reached, 


Fig.  -±37,     Engine  Timing  Gears  and  Magneto  Drive. 

which  is  just  as  the  armature  shoe  edge  leaves  the  pole  piece,  the 
breaker  points  are  opened.  The  action  is  the  same  as  for  the  low 
tension  or  battery  system.  When  the  points  open  the  lines  of  force 
collapse  or  fall  back,  cutting  the  primary  winding  which  induces  a 
higher  voltage  therein,  which  rushes  into  and  charges  the  condenser. 
The  condenser  is  mounted  in  the  end  of  the  armature.  This  con- 
denser charge  is  immediately  kicked  back  through  the  low  tension 
circuit,  thus  assisting  in  completely  demagnetizing  the  coil  core  and 
assisting  in  breaking  down  the  lines  of  force.  The  final  collapse  is 
very  rapid.     This  rapid  collapse  of  the  numerous  lines  of  force  causes 


378  Automotive  Trade  Training 

the  induction  of  a  very  high  tension  current  within  the  secondary 
v^inding.  This  is  used  to  ignite  the  charge  vi^ithin  the  cyUnder.  It 
is  taken  off  of  the  collector  or  slip  ring,  and  is  carried  to  the  center 
of  the  distributor  head  by  means  of  the  pencil  brush  or  distributing 
bar. 

The  student  v^ill  note,  however,  that  there  is  another  feature 
which  makes  the  high  tension  magneto  superior  to  the  low  tension. 
While  a  current  wave  is  being  induced  in  the  primary  winding,  one 
is  being  induced  in  the  secondary  winding  even  stronger  than  the 
first  mentioned.  This  is  induced  by  the  secondary  coil  cutting  the 
lines  of  force,  just  as  the  primary  current  is  induced.  The  voltage 
or  pressure  generated  by  this  method  is  not  sufficient  to  jump  the 
spark  plug  points,  but  it  is  there  within  the  secondary  winding 
attempting  to  flow  along  the  wire  to  the  collector  ring  brush  and 
pencil,  and  by  way  of  the  distributor  to  the  spark  plugs.  The  pres- 
sure within  the  secondary  coil  is  thus  fairly  high  when  the  contact 
points  on  the  primary  circuit  open.  The  opening  of  the  points  in- 
duces additional  current  and  this  is  high  enough  to  cause  the  current 
to  break  down  the  air  gap  momentarily.  Once  the  gap  is  broken 
down  and  the  current  flowing,  the  voltage,  which  is  generated  within 
the  secondary  coil  by  the  magnetic  lines  of  force  passing  through  the 
field  from  the  north  pole  to  the  south  pole,  is  sufficient  to  keep  the 
current  flowing  in  the  form  of  a  heavy  burning  spark.  It  is  readily 
seen  how  this  current  flowing  for  a  longer  length  of  time  (about  30 
to  40  degrees  of  armature  travel)  will  produce  better  ignition  of  the 
fuel  charge  within  the  cylinder. 

High  Tension  Inductor  Type. — In  this  type  the  general  con- 
struction follows  the  low  tension  machine  ,  of  the  same  type.  An 
additional  coil  of  fine  wire  is  placed  on  the  coil  over  the  coarser 
primary  winding.  In  this  finer  winding  the  high  tension  current  is 
induced.     The  coils  are  again  stationary  over  the  inductor  shaft  and 

mounted  between  the  inductor  arms.  These 
inductors  or  arms  form  the  path  for  the 
magnetic  flux  to  follow  as  it  flows  from  the 
north  pole  to  the  south  pole  through  the 
coil.  Except  for  the  fact  that  the  coils  are 
stationary,  and  the  absence  of  brushes  and 
slip  rings,  the  action  is  the  same  as  for  the 
armature  type. 

When  the  breaker  points  open,  a  cur- 
rent is  induced  within  the  coarse  or  primary 
winding.    This  charges  the  condenser.    The 
condenser     discharges     back     through     the 
Fig.  43,s.     High   Tension         primary  coil.  The  rapidly  collapsing  lines  of 
Magneto  (Dixie  Aero).  f^j.^^^  jnduce  a  high  tension  current  within 


Magneto  Ignition 


379 


the  coil  of  fine  wire  which  is  sufficient  to  jump  the  spark  plug  gap. 
Following  on  this  comes  the  current  induced  by  the  flux,  flowing 
through  the  high  tension  winding  from  the  one  inductor  to  the  other. 
Just  as  in  the  armature  type  this  current,  while  not  sufficient  to  jump 
the  spark  plug  gap  of  its  own  force,  will  continue  to  flow  across  the 
points  once  the  gap  has  been  jumped  and  the  resistance  overcome. 
The  condenser  is  mounted  within  the  base  or  at  some  other  point 
convenient  to  the  general  type  of  construction. 

JOB  133.     K-W  LOW  TENSION  MAGNETO   GENERATOR 

All  K-W  magnetos  are  of  the  inductor  type.     The  winding  is  stationary, 
the  magnetic  flux  being  conducted  through  the  winding  as  it  passes  from  north 


Fig.    439.      K-W    Low    Tension,   Model  DL 

pole  to  south  pole.  The  rotor  carrying  the  inductors  is  the  only  moving  part. 
The  full  action  of  the  inductors  is  explained  in  Job  134  on  the  high  tension 
type.  The  low  tension  magneto  is  of  the  high  frequency  A.  C.  type.  This 
instrument  is  used  to  provide  current  for  vibrating  coils  or  for  the  lighting 
system.     Friction   or   belt   drive   is   used.     It   is   not   necessary   to    have    the 


Fig".   440.     K-W    Low   Tension   Magneto.     Note    Inductors. 


380 


Automotive  Trade  Training 


magneto  timed  to  the  engine.  The  speed  of  the  low  tension  machine  is  from 
2000  to  3000  R.  P.  M.  Since  the  direction  of  flow  of  the  magnetic  flux  changes 
four  times  per  revolution  instead  of  twice  as  in  the  H  or  armature  type,  the 
current  pulsations  per  revolution  are  twice  as  many  or  four  instead  of  two. 
This  will  give  four  times  the  rotor  speed,  changes,  alternations  or  pulsations 
of  current  per  minute,  in  actual  figures  from  8,000  to  12,000  pulses  per  minute. 
Since  one-half  of  these  are  in  one  direction  and  the  other  in  the  other  direction 
the  current  is  not  satisfactory  for  charging  storage  batteries. 


Fig.   441.     Inductors   and    Stationary   Coil  Winding. 

The  rotor  which  is  illustrated  revolves  in  two  sets  of  the  latest  improved 
ball  bearings.  It  does  not  rub  against  or  touch  any  other  parts  of  the 
generator  as  all  other  parts  stand  still.     No  brushes  or  slip  rings  are  needed. 

Winding. — The  winding  shown  in  position  on  the  rotor  consists  of  a  strip 
of  copper  wound  spirally  around  the  core  of  the  revolving  rotor.     Terminals 


K-W  MAGNETO 


CROUNO  TO  CNCINC  FBAMC 

Fig.    442.     Low    Tension    Magneto    with  vibrating   coil. 

of  the  winding  extend  through  the  top  of  the  pole  pieces  in  which  the  rotor 
revolves.  They  are  securely  attached  to  the  binding  posts  found  at  the 'end 
of  the  generator.  The  wiring  diagram  shows  how  the  magneto  is  wired  in 
connection  with  a  quad  dash  coil  for  ignition  on  a  four-cylinder  engine. 

JOB  134.— K-W  HIGH  TENSION  MAGNETO. 

Principle   of   Operation. — The   K-W   high    tension    magneto   is   used  very 
largely  on  heavy  duty  motors,  as  trucks  and  tractors.     The  same  principle  is 


Magneto  Ignition 


381 


Fig.  443.     K-W  High  Tension  Magneto. 

used  as  in  the  high  frequency  low  tension  machine.  The  rotor  is  the  same 
general  style.  However,  the  high  tension  machine  is  fitted  with  the  usual 
circuit  breaker  and  distributing  mechanism.  It  must  be  driven  as  are  all  high 
tension  machines  in  fixed  relation  with  the  engine.  Flexible  drives  such  as 
friction  or  belts  cannot  be  used. 

Winding. — The  primary  winding  is  on  a  soft  iron  core.     Refer  to  Fig.  444. 


^     I   >  -^ — ^ 


CWCUIT  .    IRUKM 

Fig.   444.    K-W   Magneto.    Arrows   indicate   path   of   Flux. 


382 


Automotive  Trade  Training 


The  primary  winding  forms  the  core  for  the  secondary  winding,  which  is 
much  shorter  than  in  the  armature  type.  The  core  of  the  winding  is  located 
in  the  direct  path  of  the  greatest  number  of  lines  of  force  flowing  from  the 
north  pole  to  the  south  pole.  These  lines  of  force  are  indicated  by  the  arrows 
in  Figs.  444  and  445.     The  winding  is  stationary. 

Inductors,  Rotors  and  Pole  Shoes. — The  inductors  are  part  of  the  rotor. 
They  are  made  from  soft  iron  machined  to  a  close  fit  and  placed  on  the  rotor 
shaft  at  right  angles  or  ninety  degrees  apart.     The  pole  pieces  or  shoes  differ 

from  the  usual  armature  type 
and  are  mounted  on  the  ma- 
chine at  a  ninety  degree 
angle  with  respect  to  each 
other.  This  harmonizes  with 
the  rotor  construction  and 
accounts  for  the  four  current 
waves  per  revolution  of  the 
rotor.  Fig.  445  shows  the 
pole  shoes  in  section.  The 
path  offering  least  resistance 
to  the  magnetic  flux  is  in- 
dicated in  the  same  figure.  It 
enters  one  extension  of  the 
rotor  and  from  it  passes  into 
and  through  the  core  and  coil 
windings,  after  which  it  fol- 
lows along  another  arm  or 
extension  of  the  rotor  to  the 
south  pole.  The  next  extension  of  the  rotor  to  come  into  close  range  of  the 
north  pole  is  one  on  the  opposite  side  of  the  coil  or  winding.  Consequently 
the  next  wave  of  current  will  be  in  the  opposite  direction.  The  change  of 
direction  producing  A.  C.  current  is  desirable,  as  before  a  current  wave  can  be 
built  up  in  a  reverse  direction  the  core  and  winding  must  have  reached  a  2ero 
point.  In  other  words,  the  reversal  hastens  the  collapse  of  the  lines  of  force 
about  the  winding  which  is  very  much  desired  in  producing  a  hot  intense  spark. 


Fig.   445.    K-W  Magneto.     Arrows   indicate  path   of 
Magnetic  Flux. 


Fig.  446.    Simms  "C4"  4-Cylinder  Magneto. 


Magneto  Ignition 


383 


Fig.  445  shows  three  vital  positions  of  the  rotor.  At  A,  the  first  position, 
the  lines  of  force  come  down  through  the  wing  of  the  rotor,  pass  through  the 
core,  and  then  up  through  the  opposite  wing  or  extension.  In  B  the  rotor  has 
been  rotated  to  the  next  position,  while  in  C  the  position  indicated  is  the  one 
occupied  as  the  spark  is  produced  at  the  plug.  The  high  tension  spark  is 
delivered  the  instant  the  contact  points  open  so  that  the  position  C  indicates 
the  point  at  which  the  maximum  current  would  be  generated  in  the  primary. 

JOB  135.     SIMMS  HIGH  TENSION  MAGNETOS. 


Fig.  447.     Simms  "C4"  Magneto,  with  Impulse  Starter. 

Simms  magnetos  are  of  the  true  high  tension  type.  High  tension  current 
is  developed  directly  within  the  armature  without  the  introduction  of  any 
exterior  devices.  This  in  itself  is  a  considerable  advantage  over  the  low 
tension  magneto,  where  a  transformer  coil  is  used  to  step  up  the  low  tension 

current,  as  there  is  a  certain 
amount  of  current  and  time  lost 
in  this  operation.  The  result  is  a 
weaker  spark  in  the  case  of  the 
low  tension.  A  great  deal  of 
rather  complicated  wiring  is  re- 
quired for  the  low  tension 
magneto  while  the  high  tension 
requires  only  one  cable  to  each 
plug  and  one  ground  wire  con- 
nected through  a  switch. 

Pole  Shoes. — A  distinct  fea- 
,gg       ture  of  the  Simms  magnetos  is 
their   slow  speed   characteristic. 
They    will    give   a    heavy    spark 
even  when  rotated  at  speeds  of 
less  than  40  R.  P.  M.    This  fea- 
ture allows   starting  the   engine 
on  the  magneto  even  where  the 
cranking    speed     is     necessarily 
Pig.  448.    Full  back  view  showing  driving  end.      ^low.   An  inspection  of  the  cross 
Arrow  indicates  direction  of  rotation.  section    of    the    pole    shoes    and 


384 


Automotive  Trade  Training 


armature  will  show  the  student  why  the  construction  used  will  make  for  easy 
starting  even  on  a  retarded  spark.  Since  the  amount  of  current  produced  is 
dependent  on  the  number  of  lines  of  force  cut,  this  pole  shoe  is  so  designed 
as  to  cause  a  large  number  of  lines  to  flow  just  as  the  armature  breaks  from 
the  retarded  position. 

Contact  Breaker. — The  contact  breaker  is  so  designed  that  at  high  speeds 
the  action  is  assisted,  and  not  retarded  by  the  centrifugal  forces  developed. 
Thus,  there  is  never  any  danger  of  the  ignition  cutting  out  at  high  speeds. 

Armature. — The  high  tension  armature  consists  of  a  few  turns  of  heavy 
primary  wire  over  which  are  wound  many  turns  of  fine  secondary  wire. 
Enamel  insulated  wire  is  used  and  each 
layer  is  further  insulated  from  others 
with  sheets  of  oiled  silk.  After  being 
completely  wound,  the  armature  is  first 
placed  in  a  tank  under  pressure.  The 
tank  is  filled  with  insulating  liquid. 
Next  the  armature  goes  into  a  tank 
under  vacuum.  As  this  operation  is 
continued,  first  compression,  then  va- 
cuum, all  air  is  worked  from  the  arma- 
ture and  all  pores  or  small  openings 
are  filled  with  the  insulating  liquid,  or 
dielectric.  The  armature  is  next  baked 
in  ovens  to  drive  off  all  traces  of  mois- 
ture. 

Winding. — One  end  of  the  primary 
wire  is  grounded  on  the  armature  core, 
and  the  other  end  is  brought  out  to  the 
breaker  points.  The  condenser  is  con- 
nected in  parallel  to  prevent  the  points 
burning.  The  grounded  end  of  the  secondary  is  connected  to  the  primary, 
forming  a  continuation  of  the  same.  The  other  end  of  the  secondary  is  kd  to 
the  slip  ring,  then  through  the  conducting  bar  to  the  distributor,  spark  plugs, 
and  ground  on  the  engine,  to  the  magneto  base  and  back  into  the  grounded 
end  of  the  secondary. 


Fig.  449.  Showing  relative  position  of 
armature  at  both  full  retard  and  full 
advance  with  American  Simms  Patented 
Extended   Pole  Shoe. 

As  breaker  points  open  at  the  fully 
retarded  position  the  air  space  is  but 
1  m/m.  At  this  point  the  maximum 
current  is  produced  in  the  primary,  thus 
explaining  the  American  Simms  easy 
starting  feature. 


Fig.   450.     Wiring   Diagram   for   Simms   High    Tension   Magneto.      Four-Cylinder. 


Magneto  Ignition 


385 


When  the  contact  points  are  closed  the  primary  circuit  is  also  closed. 
Rotating  this  coil  through  the  magnetic  flux  induces  a  low  tension  circuit  in 
the  primary  coil.  The  primary  circuit  is  then  broken,  inducing  a  high  tension 
current  of  extreme  intensity  in  the  secondary  winding,  which  is  distributed  to 
the  spark  plugs  as  rnentioned  above. 

Driving. — The  magneto  must  be  positively  driven  by  gears  or  chain.  If 
the  latter  method  is  used  provision  must  be  made  to  take  up  the  slack  due  to 
wear.     For  a  four-cylinder  four-cycle  motor  the  magneto  is  driven  at  engine 


Fig.   451.     Wiring    diagram   for   Sims    Six-Cylinder   Magneto. 

Speed.  For  a  six-cylinder  motor  the  magneto  is  driven  at  one  and  one-half 
times  engine  speed.  The  magneto  will  operate  only  in  the  direction  shown  by 
arrows  on  the  driving  end  plate. 

Timing. — To  time  the  magneto  to  the  engine  turn  or  crank  over  until 
cylinder  No.  1  is  on  the  compression  stroke.  This  is  the  top  dead  center  with 
valves  closed.  It  is  the  beginning  of  the  working  stroke,  and  the  connecting 
rod  should  be  swung  on  the  downward  stroke  side.  Remove  the  contact 
breaker  cover  with  the  distributor  cover  or  board.  Turn  the  magneto  armature 
in  the  direction  which  it  must  run  until  the  contact  points  are  just  opening. 
The  timing  lever  must  be  in  full  retard  position.  To  secure  retard,  the  lever 
must  be  pushed  down  with  the  direction  of  turn  of  the  armature.  The 
distributor  brush  must  at  the  same  time  be  in  a  position  to  touch  the  distributor 
segment  serving  cylinder  No.  1.  The  driving  gear  or  coupling  should  then  be 
securely  tightened  onto  the  magneto  armature  driving  shaft  using  the  key  in 
the  key-way  provided  for  same.  If  it  is  a  case  of  retiming  the  magneto  this 
work  is  likely  already  done. 

With  the  engine  in  the  position  given  and  the  magneto  set  as  stated,  the 
two  are  in  proper  position  to  be  connected.  Care  must  be  exercised  to  see  that 
they  remain  in  their  relative  positions  until  finally  secured  together  in  this 
proper  relation.  It  must  always  be  remerabered  that  the  distributor  brush 
rotates  in  the  opposite  direction  to  the  armature.  Terminal  No.  2  on  the 
distributor  does  not  necessarily  lead  to  cylinder  No.  2,  but  must  lead  to  that 
cylinder  firing  second.  The  same  applies  to  cylinders  and  termnials  3  and  4 
as  well.  The  magneto  has  a  timing  range  of  30  degrees,  crank  shaft  travel. 
Any  advance  or  retard  desired  more  than  that  available  from  the  action  of  the 


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Automotive  Trade  Training 


Fig.  452.     Simms  Type  K4  Magneto. 

timing  lever  must  be  secured  on  the  engine  alone  by  advancing  or  retarding 
the  engine  timing  gears,  but  in  no  case  must  the  setting  of  the  magneto 
distributor  or  internal  armature  gears  be   disturbed,  as   these   have  a  certain 

fixed  relation  to  each  other. 
Any  different  setting  of 
these  two  gears  will  seri- 
ously impair  the  efficiency 
of  the  magneto.  If  neces- 
sary to  disassemble  these 
gears,  make  certain  the 
proper  marks  are  on  them 
to  insure  proper  reassem- 
bly. 

Oiling  Magneto.  —  The 
magneto  should  be  oiled 
every  two  weeks  or  1000 
miles  run,  with  four  or  five 
drops  of  light  machine,  not 
cylinder,  oil  in  each  of  the 
oil  holes,  which  are  located 

_  ,^..    _        „  over    the    armature    driving 

Fig.  453.     Simms  Magneto,  Type  "CK6",  Two  Spark.     ,     r^  ^u       ^  r    ^u 

shaft    near    the    top    of    the 

distributor  board.     The  contact  points  should  never  be  oiled  as  it  may  cause 

serious  trouble  and  undue  wear  of  them. 

Care  of  Contact  Breaker. — The  platinum  points  should  be  set  to  open  on 
each  cam  about  1/64".  They  should  be  kept  free  of  oil  and  clean.  They 
should  make  even  contact  over  their  entire  surface.  The  contact  breaker  lever 
should  pivot  freely  in  the  bushing,  and  should  be  inspected  occasionally  and 
freed  of  any  oil  or  dirt  accumulations.  The  points  should  be  filed  only  if 
absolutely  necessary  and  then  with  a  fine  flat  file. 

Distributor  Board. — Cable  connections  should  be  kept  tight  and  the  inside 
of  the  board  wiped  occasionally  with  a  dry  cloth  to  remove  any  oil  or  dirt. 


I 


Magneto  Ignition  387 

The  distributor  carbon  brush  should  at  all  times  press  firmly  against  the 
distributor  board. 

Safety  Spark  Gap. — The  safety  spark  gap  is  to  protect  the  insulation  of  the 
armature  from  injury  such  as  might  be  the  case  if  excessive  voltage  were  built 
up.  This  condition  would  be  present  should  a  high  tension  wire  become  loose 
or  broken.  The  high  tension  spark  will  then  jump  the  gap.  If  sparking  should 
be  detected  in  the  safety  gap  which  is  located  just  over  the  driving  spindle, 
the  high  tension  wiring  should  be  gone  over  thoroughly  at  both  the  magneto 
and  spark  plug  ends.  The  distributor  carbon  brushes  should  be  examined  to 
see  if  they  are  in  condition  and  making  contact  with  the  brass  segment  on  the 
distributor  rotor.  If  sparks  can  be  obtained  at  the  safety  gap,  it  is  an  indica- 
tion that  the  magneto  is  generating  and  that  the  trouble  is  likely  in  the  wiring 
or  spark  plugs. 

Removing  Coupling. — If  it  is  necessary  to  remove  the  coupling,  great  care 
should  be  taken  that  not  too  much  force  is  used  in  the  operation.  The  hard 
rubber  slip  ring  just  inside  the  housing  is  easily  broken.  On  no  account  should 
any  violent  blows  be  struck  on  the  end  of  the  armature  shaft.  The  garage 
press,  or  better  still,  the  properly  adjusted  gear  puller  should  be  used  if  there 
is  a  tendency  for  the  coupling  to  stick. 

Spark  Plugs. — The  plug  points  should  be  set  from  1/64''  to  -h."  apart.  The 
first  mentioned,  or  just  a  bit  over,  is  recommended.  If  the  distance  is  too 
great,  it  is  possible  that  the  motor  will  be  hard  to  start.  It  must  be  borne 
in  mind  that  while  a  spark  will  jump  the  points  when  the  plug  is  lying 
on  the  cylinder,  it  does  not  follow  that  a  spark  will  occur  when  the  plug  is  in 
the  cylinder.  The  reason  for  this  is  that  the  resistance  of  the  gases  under 
compression  is  greater  than  that  offered  by  the  atmosphere.  If  the  insulation 
of  the  plug  is  cracked  or  broken,  if  the  plug  points  are  oily,  or  if  the  insulation 
is  covered  with  carbon,  the  desired  results  will  not  be  obtained.  A  cracked 
porcelain  is  often  hard  to  detect.  The  easiest  way  is  to  insert  a  new  spark 
plug  or  one  known  to  be  right.  If  this  overcomes  the  trouble,  it  is  then  known 
to  be  with  the  plug. 

Refusal  to  Start. — Should  difficulty  be  experienced  in  starting  after  tests 
have  proven  the  plugs  are  in  proper  condition,  the  wire  connected  to  the 
contact  breaker  box  should  be  removed.  If  this  seems  to  correct  the  trouble 
the  switch  should  be  examined  and  any  corrections  necessary  should  be  made. 
The  wire  removed  is  for  the  purpose  of  short  circuiting  the  primary  current 
when  desiring  to  cut  out  the  ignition  and  stop  the  motor. 

JOB  136.  BOSCH  MAGNETOS,  DU  TYPES. 

The  types  DUl,  DU2,  DU3,  DU4,  and  DU6  magnetos  are  of  the  high 
tension  series  and  are  used  respectively  on  one,  two,  three,  four,  and  six- 
cylinder  engines  of  the  automobile  type  in  motor  car,  marine,  tractor,  and 
stationary  service.  The  type  DU  magnetos  are  usually  used  as  sole  ignition 
on  an  engine,  or  in  some  cases  in  connection  with  a  battery  system  operating 
on  a  separate  set  of  spark  plugs.  The  DU  magnetos  are  also  used  to  provide 
battery  and  magneto  ignition  with  one  set  of  plugs.  This  is  without  alteration 
and  is  accomplished  as  indicated  in  Job  142  describing  the  Bosch  Vibrating 
Duplex  Ignition  System. 

Generation  of  Current. — The  high  tension  current  is  generated  within  the 
armature,  without  the  aid  of  any  step-up  coil.  The  timer  and  distributor  are 
integral.  The  armature  winding  is  composed  of  two  sizes,  one  heavy  and  the 
other  comparatively  fine.  The  heavy  wire  is  used  as  the  primary  or  low 
tension  circuit,  while  the  very  fine  wire  is  the  secondary  circuit.  The  rotation 
of  the  armature  between  the  poles  of  strong  permanent  magnets  sets  up  or 


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Automotive  Trade  Training 


induces  a  current  within  the  armature  primary  circuit.  This  is  further 
augmented  at  regular  intervals  in  the  rotation  of  the  armature  shaft  by  the 
abrupt  interruption  of  the  primary  circuit  by  means  of  breaking  the  magneto 
interrupter  points.  At  the  opening  of  the  primary  circuit  the  resultant  dis- 
charge of  current  from  that  circuit  induces  a  current  of  high  voltage  within 
the  secondary  winding  of  the  armature.  The  high  tension  current  thus  induced 
is  collected  by  the  collector  ring  on  the  armature  and  passed  through  the 
collector  brush,  then  to  the  various  magneto  distributor  terminals,  each  of 
which  is  connected  by  cable  to  the  spark  plug  of  its  respective  cylinder.  The 
operation  will  be  more  completely  understood  by  referring  to  Fig.  454  which 
shows  the  complete  primary  and  secondary  circuits. 


I^^•ERRUPT£R 

Fig.  454.     Circuiit  Diagram  Type  DU4  Bosch  Magneto. 

Primary  or  Low  Tension  Circuit. — The  beginning  of  the  armature  primary 
winding  is  in  metallic  contact  with  the  armature  core.  The  other  end  of.  the 
primary  winding  is  connected,  by  means  of  the  interrupter  fastener  screw,  to 
the  insulated  contact  block  supporting  the  long  platinum  contact  on  the 
magneto  interrupter.  The  interrupter  lever,  carrying  a  short  platinum  contact, 
is  mounted  on  the  interrupter  disk  which,  in  turn,  is  electrically  connected  to 
the  armature  core.  The  primary  circuit  is  completed  or  made  whenever  the 
two  contacts  are  brought  together,  and  interrupted  when  the  cams  on  the 
breaker  mechanism  cause  these  points  to  separate.  The  separation  of  the  points 
is  controlled  by  the  action  of  the  interrupter  lever  as  it  bears  against  the  steel 
cams  secured  to  the  inner  surface  of  the  interrupter  housing.  The  high  tension 
current  is  generated  in  the  secondary  winding  only  when  there  is  an  interrup- 
tion of  the  primary  circuit.  The  spark  occurs  the  instant  the  platinum  points 
are  opened. 

Secondary  or  High  Tension  Circuit. — The  armature  secondary  circuit  is  a 
continuation  of  the  armature  primary  circuit,  the  beginning  of  the  secondary 
being  connected  to  the  primary,  while  the  end  of  the  secondary  is  connected 
to  the  insulated  collector  ring.  This  is  mounted  on  the  armature  shaft  just 
inside  the  driving  shaft  end  plate  of  the  magneto.  The  collector  brush,  which 
is  held  in  contact  with  the  collector  ring  by  the  brush  holder  at  the  shaft  end  of 
the  magneto,  receives  the  high  tension  current  collected  by  the  collector  ring, 
and  by  means  of  the  conducting  bar  under  the  arch  of  the  magneto,  passes  the 
current  to  the  metal  contact  in  the  center  of  the  distributor  plate.  From  the 
latter  point  the  high  tension  current  passes  to  the  distributor  brush  which  is  held 
in  a  brush  holder  mounted  on  the  distributor  gear,  and  consequently  rotates 
with  the  gear. 


Magneto  Ignition  389 

Distributor. — Metal  segments  are  molded  into  the  distributor  plate,  and  as 
the  distributor  brush  rotates  it  makes  contact  successively  with  these  segments. 
The  segments  in  turn  are  connected  with  the  terminal  studs  on  the  face  of  the 
distributor  plate.  The  latter  are  connected  by  cable  to  the  spark  plugs  in  the 
various  cylinders.  In  the  cylinder  the  current,  in  the  form  of  a  jump  spark, 
ignites  the  fuel  charge  and  then  returns  to  the  magneto  armature  through  the 
engine  castings.     This  completes  the  circuit. 

Safety  Spark  Gap. — In  order  to  provide  protection  for  the  armature  and 
other  current-carrying  parts  the  magneto  is  equipped  with  a  spark  gap  called 
the  safety  gap.  Under  ordinary  circumstances  the  current  will  follow  its 
normal  path  to  the  spark  plugs,  but  if  for  any  reason  the  electrical  resistance 
in  the  secondary  circuit  is  increased  to  a.  high  point  as  when  a  cable  becomes 
disconnected,  or  a  spark  plug  gap  too  wide,  the  high  tension  circuit  will 
discharge  across  the  safety  gap.     Otherwise  it  is  inoperative. 

The  current  should  never  be  allowed  to  pass  across  the  safety  spark  gap 
for  any  length  of  time.  If  the  engine  is  to  be  operated  on  an  auxiliary  ignition 
system,  the  magneto  must  be  grounded  in  order  to  prevent  the  production  of 
high  tension  current.  The  switching  off  of  the  magneto  switch  will  accomplish 
this  by  grounding  the  primary'  circuit.  The  snapping  sound  by  which  the 
passage  of  current  across  the  safety  gap  may  be  noticed  should  always  lead  to 
an  immediate  search  for  the  difficulty. 

The  safety  spark  gap  is  arranged  on  the  dust  cover  over  the  armature,  and 
consists  of  two  short  pointed  electrodes  supported  a  short  distance  from  each 
other.  One  electrode  is  set  on  the  dust  cover  itself  and  enclosed  by  a  metal 
and  wire  gauze  housing.  The  other  electrode  which  is  the  insulated  one  is 
set  in  a  steatite  cover  of  the  safety  spark  gap  housing  and  is  connected  in  the 
secondary  circuit  of  the  magneto. 

Timing  Range. — The  magneto  interrupter  housing  is  arranged  so  that  it 
may  be  rotated  through  an  angle  of  35  degrees  with  respect  to  the  armature 
shaft.  The  movement  of  this  housing  in  one  direction  or  the  other  causes  the 
interrupter  lever  to  strike  the  steel  cams  earlier  or  later  in  the  revolution  of 
the  armature.  This  causes  the  spark  to  occur  earlier  or  later  with  relation  to 
the  stroke  of  the  piston. 

The  spark  can  be  advanced  by  moving  the  interrupter  housing  by  means 
of  the  timing  control  arm  in  the  direction  opposite  the  rotation  of  the  armature. 
To  retard  it,  move  in  the  direction  of  rotation  of  the  magneto  armature.  The 
armature  rotation  is  indicated  by  the  arrow  on  the  oil  well  cover  at  the  driving 
shaft  end  of  the  magneto. 

Cutting  out  the  Ignition. — Since  high  tension  current  is  generated  only  on 
the  interruption  of  the  primary  circuit,  it  is  evident  that  to  cut  out  the  ignition 
it  is  necessary  merely  to  divert  the  primary  current  to  a  path  which  is  not 
affected  by  the  action  of  the  magneto  interrupter.  This  is  accomplished  as 
follows: 

An  insulated  grounding  terminal  is  provided  on  the  magneto  interrupter 
housing,  with  its  inner  end,  consisting  of  a  spring  with  carbon  contact,  pressing 
against  the  head  of  the  interrupter  fastening  screw.  The  outer  end  of  the 
grounding  terminal  is  connected  to  a  switch.  Low  tension  cable  is  used  for 
this.  The  other  side  of  the  switch  is  grounded  by  connecting  it  to  the  engine 
or  other  metallic  part  of  the  chassis. 

When  the  switch  is  open  the  primary  current  follows  its  normal  path  across 
the  platinum  interrupter  contacts,  being  interrupted  at  each  break  of  these 
points.  However,  when  the  switch  is  closed  the  current  passes  from  the  head 
of  the  interrupter  fastening  screw  through  the  grounding  terminal  cable  and 
switch  to  the  engine  and  thus  back  to  the  armature.     Since  the  primary  current 


390 


Automotive  Trade  Training 


Fig.  455.    Bosch  Magneto. 


is  not  Interrupted  in  this  flow  no  high  tension  current  is  generated  or  induced 
within  the  secondary  winding. 

Oiling. — Aside  from  keeping  the  magneto  clean  externally  about  the  only 
care  needed  is  oiling  of  the  bearings.     There  are  two  ball  bearings  supporting 

the  armature  and  a  plain  bearing 
supporting  the  shaft  of  the  distribu- 
tor gear. 

Any  good  light  machine  oil  may 
be  used  for  this,  but  cylinder  oil 
should  not  be  used.  Each  of  the 
bearings  should  receive  two  or  three 
drops  each  500  miles  run.  This 
should  be  applied  through  the  oil 
ducts  under  the  covers  marked  "oil" 
located  at  each  end  of  the  magneto. 
The  interrupter  is  intended  to 
operate  without  lubrication.  Oil  on 
the  platinum  breaker  points  will  pre- 
vent good  contact  causing  sparking 
and  burning  as  well  as  misfiring. 
Care  should  be  exercised  to  prevent 
oil  entering  to  these  parts. 

Starting  the  Engine.  —  When 
cranking  a  motor  equipped  with  the 
D.'  U.  magneto  as  sole  ignition,  the  spark  lever  should  be  advanced  a  slight 
distance.  In  some  cases  of  properly  timed  magnetos  the  advance  may  be 
one-third  the  full  advance  for  hand  cranking,  and  as  much  as  one-half  for 
starting  motor  work.  This  will  permit  easier  starting.  The  most  effective 
point  for  starting  is  quickly  learned  from  actual  experience.  In  hand  cranking 
full  advance  is  very  likely  to  result  in  injury  to  the  operator,  and  in  starting 
motor  work  may  result  in  injury  to  the  apparatus. 

Ignition  Troubles. — Ignition  troubles  with  the  Bosch  magneto  may  be 
divided  into  two  classes.  The  first  of  these  is  spark  plug  trouble,  the  second, 
comparatively  infrequent,  magneto  trouble.  In  the  case  of  defective  ignition 
the  first  pomt  to  determine  is  whether  the  trouble  is  with  the  plugs  and  external 
circuits,  or  within  the  magneto  itself.  In  general,  when  only  one  cylinder 
misfires,  the  trouble  is  with  the  plug. 

Plug  Gap  too  Wide. — The  distance  between  the  electrodes  of  the  spark 
plugs  varies  according  to  the  individuality  of  the  engines,  but  normally  this 
distance  should  not  be  less  than  one-fiftieth  inch.  On  the  other  hand,  however, 
too  wide  a  gap  increases  the  resistance  and  interferes  with  the  proper  genera- 
tion of  current  at  low  speeds.  Difficulty  in  starting  an  engine  and  missing  at 
low  speeds  are  very  often  due  to  the  spark  plug  gaps  being  too  wide.  As  the 
actual  use  qf  the  plugs  shows  a  tendency  for  the  spark  to  burn  the  plug  gap 
wider,  it  is  well  to  inspect  the  plugs  from  time  to  time  to  make  sure  that  the 
gap  is  not  too  great.  Readjusting  the  electrodes  will  remove  any  gap  troubles. 
Unless  quite  experienced,  the  mechanic  should  test  his  work  to  see  that  all 
plugs  are  adjusted  equally.     If  not,  the  motor  will  operate  unevenly. 

Plug  Short-circuited. — This  is  usually  caused  by  a  cracked  or  porous 
insulator.  Any  of  these  conditions  will  cause  misfiring  by  permitting  the 
current  to  stray  from  its  intended  path. 

Cables. — Misfiring  of  one  cylinder,  either  continuous  or  intermittent,  may 
be  due  also  to  a  chafed  or  broken  cable,  or  loose  cable  connection.  The  cables 
should  receive  careful  examination,  special  attention  being  paid  to  the  insula- 
tion.    The  metal  parts  of  the  cables  must  not  come  in  contact  with  any  metal 


Magneto  Ignition  3"9l 

parts  of  the  engine  or  magneto,  except  those  designated  as  being  correct  in  the 
instructions  preceding  this. 

Ignition  Fails  Suddenly. — A  sudden  failure  of  the  ignition  may  indicate  a 
short  in  the  low  tension  cable.  This  condition  may  be  caused  by  the  presence 
of  moisture  or  dirt,  defects  in  the  cable  or  cable  insulation,  or  to  faulty 
connections  at  the  switch  or  even  a  short-circuited  switch  due  to  the  failure  of 
the  switch  mechanism.  A  test  for  trouble  in  the  switch  and  low  tension  cable 
is  quickly  made  by  removing  the  cable  from  the  grounding  terminal  on  the 
cover  of  the  magneto  interrupter  housing,  and  then  attempting  to  start  the 
motor  on  the  magneto.  If  the  engine  runs  with  this  wire  disconnected,  but 
stops  when  the  wire  is  replaced,  it  is  evident  that  the  magneto  is  in  good  order 
and  that  the  trouble  is  due  to  some  fault  in  the  switch  or  grounding  wire, 
permitting  the  same  condition  to  exist  as  is  designed  and  used  to  stop  the 
engine  by  cutting  out  the  low  tension  current  from  the  breaker  points. 

Irregular  Firing. — If  the  cables  and  plugs  are  in  good  condition  and  the 
ignition  is  irregular  the  trouble  probably  is  with  the  magneto.  First  carefully 
examine  the  interrupter.  It  should  be  seen  that  the  interrupter  moves  freely 
on  its  pivot,  that  the  hexagonal  headed  fastening  screw  in  the  center  of  the 
interrupter  is  properly  tightened,  and  that  the  two  platinum  interrupter  contacts 
are  properly  fastened  in  position. 

If  the  interrupter  lever  does  not  move  freely  on  its  pivot,  which  is  some- 
times possible,  particuarly  with  new  magnetos,  the  hole  in  the  fiber  bushing,  in 
which  the  lever  pivots,  may  be  slightly  enlarged.  Either  a  reamer  or  small 
round  file  may  be  used  to  remedy  the  trouble.  The  reamer  is  to  be  preferred 
to  the  file,  but  no  matter  which  method  is  used  the  work  must  be  very  carefully 
done  or  the  hole  will  be  made  too  large.  A  very  little  reaming  accomplishes 
the  desired  result. 

Platinum  Interrupter  Contacts. — The  platinum  interrupter  contacts  should 
be  examined  for  the  correctness  of  their  adjustment,  and  they  should  be  so  set 
that  they  separate  0.4  of  a  millimeter,  or  about  one-sixty-fourth  of  an  inch., 
when  the  interrupter  lever  is  resting  on  either  of  the  segments  in  the  interrupter 
housing.  The  strip  of  steel  attached  to  each  magneto  wrench  is  to  be  used 
for  this  test.  A  wrench  is  furnished  with  each  new  machine  or  may  be 
purchased  from  the  dealer. 

The  adjustment  of  the  platinum  points  may  be  made  by  loosening  the  lock 
nut  of  the  long  contact  screws,  which  passes  through  the  interrupter  contact 
block,  and  turning  the  head  of  the  screw  with  the  magneto  adjusting  wrench. 
When  the  proper  adjustment  is  made  care  should  be  used  to  tighten  the  lock 
nut  firmly. 

The  platinum  contacts  of  the  interrupter  should  be  clean  and  in  proper 
alignment  with  each  other.  Any  oil  or  grease  accumulating  on  them  should 
be  removed  as  should  any  form  of  dirt.  If  contacts  are  in  bad  condition,  or 
uneven,  they  may  be  smoothed  by  means  of  a  fine  flat  jeweler's  file.  The 
platinum  contacts  should  be  kept  clean.  When  in  that  condition  and  given  proper 
attention,  a  maximum  amount  of  service  may  be  expected  from  them.  They 
should  not  be  filed  unless  this  is  found  to  be  absolutely  necessary. 

Removing  Interrupter. — The  interrupter  may  be  taken  out  as  a  unit  by 
removing  the  interrupter  housing  and  then  the  interrupter  fastening  screw  in 
the  center  of  the  interrupter.  The  magneto  wrench  fits  this  screw  head. 
Should  the  interrupter  stick  on  its  seat,  it  may  be  pried  loose  by  means  of  two 
small  screw  drivers  inserted  back  of  the  interrupter  disk,  one  on  each  side. 
When  replacing  the  interrupter  care  must  be  used  to  have  the  key  on  the 
interrupter  disk  fit  into  the  keyway  in  the  armature  shaft. 

Damaged  Insulating  Parts. — As  it  sometimes  happens  that  brush  holders 
and  other  insulating  parts  are  damaged  through  accident  or  carelessness,  these 


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parts  should  also  be  carefully  examined,  for  possible  disarrangement  or  damage 
of  the  insulation  which  might  permit  leakage  of  current. 

Summary  of  Ignition  Troubles.— In  brief,  granting  that  the  magneto  is 
properly  timed  to  the  engine,  trouble  due  to  ignition  may  be  as  follows: 

Engine  will  not  start.  Switch  is  closed,  switch  or  switch  wire  short-cir- 
cuited, interrupter  lever  sticks,  defective  plugs  or  disconnected  cables. 


M    V    N    L 

Fig.   456.     Vertical    Section    of   B4   Magneto. 


D^  Q   M    T    S    R  W 

Fig  457.     Horizontal  Section  B4  Magneto  Type. 


A.  Armature. 

B.  Condenser. 

C.  Distributor   rotor. 
I>.  Collector   ring. 

E.  Collector  brush. 

F.  Collector  brush-holder. 

G.  Armature  gear. 
H.  Distributor  gear. 

I.  Distributor  rotor  shaft 

J.  Shaft  adapter  head. 

K.  Distributor  block. 

L,.  Terminal   nut. 

M.  Interrupter  disc. 


N.  Contact  block. 

O.  Interrupter  fastening  screw. 

P.  Contact  screw — long. 

Q.  Rear  end-plate. 

R.  Interrupter  lever. 

S.  Interrupter  operating  spring. 

T.  Interrupter  housing. 

U.  Interrupter  housing  control  arm. 

V.  Interrupter  cam. 

W.  End  cap. 

X.  End  cap  contact  spring  with  brush. 

Y.  Holding  post   spring. 

Z.  Distributor  brush. 


Engine   stops   abruptly.     Switch   is   closed,   switch   or   switch   wire    short- 
circuited. 

Misfiring  at  slow  speeds  is  usually  due  to  a  too  wide  spark  gap. 

Misfiring  at  all  speeds.     Spark  plug  may  be  dirty  or  defective,  improper 


Magneto  Ignition  393 

spark  plug  gap,  cable  insulation  chafed,  cable  connections  loose,  brush 
holder  defective,  platinum  interrupter  contacts  dirty  or  oily,  interrupter  lever 
sticks. 

Timing  the  DU  Magneto  to  the  Engine. — The  crank  shaft  must  be  rotated 
to  bring"  the  piston  in  cylinder  No.  1  to  top  dead  center  on  the  compression 
stroke.  The  piston  must  be  maintained  in  that  position.  The  magneto  is  then 
to  be  secured  in  position  on  its  bracket  on  the  engine.  The  timing  control 
lever  must  be  placed  in  retarded  position.  Next  remove  the  distributor  plate 
by  withdrawing  the  two  holding  screws,  or  depressing  the  two  catch  springs 
as  the  case  may  be,  thus  exposing  the  distributor  gear  and  brush.'  The  cover 
of  the  magneto  interrupter  housing  should  next  be  removed  to  permit  obser- 
vation of  the  interrupter. 

Next  rotate  the  armature  in  the  direction  the  engine  will  turn  it,  which  must 
in  all  cases  correspond  to  the  direction  indicated  by  the  arrow  on  the  oil  cup 
cover.  To  rotate  this,  the  distributor  gear  may  be  used.  Continue  to  rotate 
the  armature  until  the  contact  points  are  just  about  to  separate,  which  occurs 
when  the  interrupter  lever  begins  to  bear  against  one  of  the  cams,  or  steel 
segments  of  the  interrupter  housing. 

The  armature  should  be  held  in  that  position  until  the  magneto  drive  is 
connected  to  the  engine,  due  care  being  taken  that  the  piston  of  No.  1  cylinder 
is  as  previously  placed,  exactly  on  top  dead  center  of  the  compression  stroke. 
The  installation  is  completed  by  replacing  the  breaker  box  cover  and  the 
distributor  plate.     To  wire  the  plugs  proceed  as  follows: 

Wiring  Spark  Plugs. — With  the  engine  and  magneto  set  up  and  connected 
as  just  suggested,  the  next  step  is  to  observe  which  brass  segment  in  the 
distributor  plate  will  be  in  contact  with  the  carbon  distributor  brush  as  the 
points  break.  A  high  tension  cable  or  spark  plug  wire  is  to  be  run  from  that 
segment,  or  rather  from  the  terminal  stud  representing  that  segment  to  the 
plug  in  cylinder  No.  1.  The  terminal  stud  next  to  receive  a  high  tension 
current  will  be  determined  by  the  direction  of  rotation  of  the  magneto.  In  all 
cases  of  gear-driven  distributors  this  direction  is  just  the  reverse  of  that  of  the 
travel  of  the  armature.  Having  determined  which  one  of  the  terminal  studs 
receives  the  second  spark,  the  cable  must  be  led  from  it  to  the  next  cylinder 
to  be  fired.  The  third  segment  in  order  of  rotation  must  be  connected  to  the 
third  cylinder  to  be  fired  and  the  fourth  segment  to  the  fourth  cylinder,  and  so 
on  if  more  than  four  cylinders  are  used.  Wires  should  be  put  on  in  workman- 
like manner  and  carried  through  some  form  of  support  which  will  protect  them 
from  heat,  oil,  dirt,  and  accident. 

JOB  137.     BOSCH  HIGH  TENSION  MAGNETO  B4  AND  B6  TYPES. 

These  magnetos  with  the  exception  of  the  distributor  are  the  counterpart 
of  the  DU  types  previously  described,  and  are  illustrated  in  Fig.  459. 

The  cable  showing  on  the  side  carries  the  high  tension  current  from  the 
collector  ring  to  the  center  of  the  distributor  from  which  point  it  is  distributed 
to  the  separate  cables  leading  to  the  plugs. 

Fig.  458  shows  the  wiring  diagram  for  the  B4  type.  The  winding  as 
described  for  the  other  Bosch  types  applies  equally  here.  The  safety  gap  is 
a  threaded  electrode  projecting  through  the  top  of  the  magneto  frame  into  the 
magneto  just  over  the  collector  ring. 

Figs.  456  and  457  are  in  section.  The  names  of  the  parts  as  shown  here  are 
applicable  to  the  other  Bosch  high  tension  types. 

The  placing  of  the  distributor  in  the  upright  position  is  a  distinct  advantage 


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Automotive  Trade  Training 


0ISTRIBUT09 


Fig.  458.     Circuit  Diagram  Type  B4  Bosch  Magneto. 


Fig.  459.  . 

Bosch   Type  B4  and  B6  Magnetos. 

and  makes  for  cleanliness  and  ease  of  inspection.     Wiring  is  also  simpler,  since 
there  are  fewer  angles  to  carry  the  wires  through. 

Another  distinct  advantage  of  this  type  over  the  earlier  types  is  the  unit 
frame  construction  which  renders  the  parts  fully  dust  and  water-proof. 


Fig.  460.    Bosch   BT4  Magneto   With   Impulse   Starter. 


Battery  Ignition 


395 


JOB  138.     BOSCH  HIGH  TENSION  MAGNETOS,  TYPES  ZR4  AND  ZR6. 

These  magnetos  are  for  use  on  the  four  and  six-cylinder  engines.  They 
are  used  as  independent  ignition.  They  are  also  used  in  connection  with  the 
separate  battery  system.  The  battery  and  magneto  systems  have  nothing  in 
common,  each  being  provided  with  its  own  set  of  plugs,  etc.  The  action  of 
the  magneto  is  closely  related  to  the  DU4  and  DU6  described  in  Job.  136. 

Primary  on  Low  Tension  Circuit. — The  end  of  the  armature  primary  circuit 
winding  is  in  contact  with  the  armature  core.  This  provides  a  ground 
connection.  The  other  end  of  the  primary  winding  is  connected  by  means  of 
the  interrupter  fastening  screw  to  the  insulated  contact  block  supporting  the 

long  platinum  contact  on  the  magneto 
interrupter.  The  interrupter  lever 
carrying  the  short  contact  is  mounted 
on  the  interrupter  disk,  thereby 
grounding  it.  The  primary  circuit  is 
completed  whenever  the  two  platinum 
contacts  are  brought  together,  the 
magneto  armature  being  in  motion. 
Likewise  it  is  broken  or  interrupted 
when  the  points  separate.  The 
separation  of  the  platinum  contacts  is 
controlled  by  the  action  of  the  inter- 
rupter lever  as  it  bears  against  the 
two  steel  segments  mounted  within 
the  interrupter  housing. 

At  the  instant  the  interrupter 
points  break,  the  collapse  of  the  lines 
of  force  about  the  secondary  winding 
is  sufficiently  fast  to  induce  the  required  high  tension  current  to  jump  the 
spark  plug  gap. 

Secondary  Winding. — The  secondary  winding  is  a  continuation  of  the 
armature  primary  winding.  The  beginning  of  the  secondary  is  connected  to 
the  primary,  while  the  other  end  of  the  secondary  is  connected  to  the  insulated 
collector  ring,  or  slipring.  The  high  tension  current  is  taken  ofif  the  slipring 
by  the  slipring  or  collector  ring  brush.  The  conductor  bar  under  the  arch  of 
the  magnets  carries  the  current  from  the  brush  to  the  center  of  the  distributor 


Fie:.   461.     Bosch  ZR6  MaernetC- 


INTERRUPTER 


Pig.    462.     Circuit    Diagram    Type    ZR4    Bosch    Magneto.     Note — Spark    plugs    must    be 
connected  in   accordance  with  firing  order  of  engine. 


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Automotive  Trade  Training 


plate.  The  metal  brush  carried  by  the  distributor  gear  has  one  end  in  contact 
with  this  solid  metal  center.  As  the  gear  revolves,  the  other  end  is  brought 
into  contact  with  the  first  one  and  then  another  of  the  metal  segments 
embedded  in  the  distributor  plate.  There  are  either  four  or  six  of  these  seg- 
ments depending  on  whether  the  magneto  is  a  ZR4  or  a  ZR6.  The  segments 
in  turn  are  connected  with  the  terminals  on  the  outside  of  the  plate.  High 
tension  cables  connect  these  terminals  with  the  proper  plugs. 

Safety  Spark  Gap. — The  usual  safety  spark  gap  is  provided.     Under  normal 
conditions  the  current  will  follow  the  spark  plug  cable  to  the  plug,  but  if  for 


Fig.  463.     Shaft  end  view  with  hood  ix-moved.  showing  slipring  brush  holder  and 

safety   spark  gap. 

any  reason  the  electrical  resistance  in  the  secondary  circuit  becomes  too  great, 
as  when  a  cable  becomes  broken,  or  disconnected,  or  the  plug  gap  too  wide, 
the  high  tension  current  will  discharge  across  the  safety  gap. 

The  current  should  never  be  allowed  to  pass  across  the  safety  gap  for  any 
length  of  time.  To  permit  this  is  likely  to  result  in  serious  damage  to  the 
winding.  The  fact  that  it  is  jumping  the  gap  is  detected  by  the  snapping 
sound.  The  gap  consists  of  a  pointed  metal  electrode  projecting  from  the 
mounting  flange  of  the  slipring  brush  holder,  inside  the  shaft  end  plate  hood. 
The  tip  of  the  electrode  is  extended  to  within  a  short  distance  of  the  metal 
part  of  the  connecting  bar  running  between  the  collector  ring  brush  and 
distributor  plate. 

Timing  Range. — The  magneto  interrupter  housing  is  so  designed  and 
constructed  that  it  may  be  rotated  from  34  to  37  degrees  with  respect  to  the 


Fig.  464. 


View  with  distributor  plate  and  interrupter  housing  removed  showing 
distributor  segments,   distributor  brush,  interrupter,  etc. 


Magneto  Ignition 


397 


rotation  of  the  armature  shaft.  The  rotation  of  this  housing  with  the  direction 
the  armature  turns  causes  the  spark  to  occur  later  or  to  be  retarded  with 
relation  to  the  point  the  piston  is  in,  and  to  the  top  of  the  cylinder  at  the  time 
the  spark  occurs.  Rotating  the  housing  toward  the  turning  armature,  or  in  the 
direction  opposite  to  which  it  is  turning,  will  advance  the  spark.  By  this  is 
meant  that  the  spark  will  occur  earlier  with  reference  to  the  travel  of  the 
piston  within  the  cylinder.  A  fully  retarded  spark  occurs  after  the  piston  has 
passed  top  dead  center.  A  fully  advanced  spark  occurs  before  the  piston  has 
reached  top  dead  center. 

The  arrangement  for  advancing  or  retarding  the  spark  is  in  two  sections. 
The  interrupter  housing  and  segments  constitute  one  segment,  while  the  timing 
control  arm  is  the  second  part.  The  construction  is  such  as  to  permit  the 
timing  control  arm  to  be  set  in  any  desired  position  on  the  interrupter  housing. 
This  facilitates  the  adjustment  for  advancing  and  retarding  the  spark. 

Further  Instructions. — Cutting  out  the  ignition,  care  and  maintenance, 
magneto  troubles,  adjusting  platinum  points,  and  the  installation  and  timing 
of  the  ZR  magnetos  is  very  similar  to  that  of  the  DU  types.  The  student 
should  refer  to  Job  136  for  instruction  covering  these  and  other  points  of 
desired  information. 

JOB  139.     BOSCH  NU4  HIGH  TENSION  MAGNETO. 

This  magneto  is  suitable  only  for  engines  of  the  four-cylinder  automobile 
type,  rated  at  or  under  about  30  H.  P.  This  magneto  may  be  used  as  the  sole 
ignition  or  in  cojunction  with  the  Bosch  Vibrating  Duplex  Coil,  thus  giving 
battery  ignition  for  starting.  The  magneto  is  of  the  Shuttle  or  H  armature 
type,  the  entire  current  generated  within  the  armature  being  delivered  to  the 
spark  plugs  without  loss  or  lag.  The  sparks  so  delivered  are  of  sufficient 
intensity  to  insure  the  combustion  of  relatively  poor  mixtures. 

The  distinct  gear  driven  distributor  common  to  other  high  tension  types  is 
omitted  in  the  NU4  magneto  and  in  its  stead  is  a  double  slipring  combining  the 

functions  of  current  collector 
and  distributor.  The  result  is  a 
considerable  reduction  in  the 
number  of  moving  parts,  with  a 
corresponding  lessening  of  the 
possibilities  of  wear  and  noise. 
It  is  also  of  less  weight.  As  in 
other  types,  the  current  is  in- 
exhaustible and  is  available  at 
low  speeds.  The  wiring  is  the 
simplest  possible.  Aside  from 
the  switch  wire  the  only  cables 
used  are  those  running  to  the 
plugs.   , 

Secondary  or  High  Tension 
Circuit. — The  primary  circuit  is 
very  similar  to  that  of  the  DU 
magnetos  described  elsewhere. 
The  secondary  winding  is  in- 
sulated from  the  primary.  The 
two  ends  of  the  secondary  wind- 
ing are  connected  to  the  two 
metal  segments  in  the  slipring 
mounted  just  inside  the  driving 
shaft  end  plate  of  the  machine. 


^^_ 


Fig.  465. 


View  of  Double  Brush  Holder. 
NU4    Magneto. 


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Automotive  Trade  Training 


The  slipring  has  two  grooves  each  containing  one  of  the  two  metal  segments. 
These  segments  are  set  diametrically  opposite  each  other,  i.e.,  180  degrees 
apart.  The  segments  are  insulated  from  each  other  as  well  as  from  the 
armature  and  magneto  frame. 

Four  Slipring  Brushes. — These  brushes  are  part  of  the  secondary  circuit 
and  are  supported  by  two  brush  holders,  one  on  each  side  of  the  driving  shaft 
end  plate.  Each  holder  carries  two  brushes  so  arranged  that  each  brush  bears 
against  the  slipring  in  separate  grooves.     On  rotating  the  armature  one  brush 


Pig.    466.     Showing    tlie    Interrupter    of    the    "NU4"    Magneto. 

makes  contact  with  the  metal  segment  in  one  groove,  while  a  brush  in  the 
holder  on  the  opposite  side  of  the  magneto  makes  contact  with  the  segment 
in  the  other  groove.  The  marks  1  and  2  appearing  on  the  brush  holders  mean 
pairs  of  brushes  receiving  simultaneous  contact.  Those  marked  1  constitute 
one  pair,  and  those  marked  2  the  other  pair. 

A  Spark  Caused  at  Two  plugs  Simultaneously. — It  is  important  to  note 
that  as  two  of  the  four  slipring  brushes  receive  contact  at  the  same  time,  and 
as  each  is   connected  by  cable  to  a  spark  plug  in   one   of  the   cylinders,  the 


Fig.  407.     Wiring  diagram  of  "NU4". 


Magneto  Ignition 


399 


secondary    circuit    always    includes    two    plugs.     The    spark    occurs    in    two 
cylinders  simultaneously. 

Timing  Magneto  to  Engine. — It  should  be  taken  into  consideration  that, 
since  at  each  interruption  of  the  primary  circuit  a  spark  occurs  at  two  plugs, 
the  four  effective  sparks  required  for  the  four  cylinders  each  two  revolutions 
of   the   crank   shaft   are   accompanied   by   four   surplus   sparks.     Each   cylinder 


Fig.  468.    Showing  Position  of  the  Slipring  Brushes 
With  Relation  to  the  Slipring. 

receives    alternately    one    effective    spark    and    one    surplus    spark,    the    latter 

occurring  exactly  360  degrees  behind  the  former. 

In    coupling   the    magneto    to    the    engine    care   should    be   taken    that   the 

platinum  points  do  not  separate 
too  late  in  their  relation  to  the 
stroke  of  the  piston.  Should 
this  happen,  the  surplus  spark 
will  occur  after  the  inlet  valve 
has  opened.  With  the  magneto 
correctly  timed,  the  spark  al- 
ways occurs  during  the  exhaust 
stroke.  With  the  average  four- 
cycle engine,  the  inlet  valves  of 
which  open  when  the  piston  is 
at  top  dead  center,  or  slightly 
past  that  position,  the  proper 
results  are  obtained  by  timing 
the  magneto  as  follows: 

Piston  No.  1  is  brought  to 
exact  top  dead  center  of  the 
compression  stroke.  While 
maintained  in  this  position,  the 
interrupter  housing  is  placed  in 
retarded  position.  The  magneto 
may  be  bolted  to  its  seat  on  the 
bracket.      Next    remove    one    of 


Fig.      4r>9.     Method      of      Removing     Brush 

holders.      With    the    Spring    Pushed 

Down,   the   Holder  Slips  Out. 


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Automotive  Trade  Training 


the  brush  holders,  Fig.  469,  to  permit  observation  of  the  slipring.  The  arma- 
ture shaft  is  now  rotated  in  the  direction  in  which  it  will  drive  until  the  begin- 
ning of  the  metal  slipring  segment  is  visible  in  the  slipring  groove  corresponding 
to  Fig.  "1"  of  the  brush  holder  which  has  been  removed.  Next  remove  the 
cover  of  the  interrupter  housing.  Further  rotate  the  armature  until  the  plati- 
num points  are  on  the  point  of  breaking.  This  point  is  reached  when  the 
interrupter  lever  bears  on  the  steel  cam  or  segment  of  the  interrupter  hous- 
ing. 

The  armature  is  held  in  that  position  while  the  magneto  drive  is  con- 
nected to  the  engine  piston  No.  1,  being  as  formerly  placed.  Next  carefully 
replace  the  brushes  and  brush  holder.  Replace  the  breaker  box  cover.  Next 
connect  the  cable  from  one  of  the  No.  1  brushes  to  cylinder  No.  1,  and  the 
other  No.  1  brush  to  cylinder  4.  The  other  two  cables  go  to  the  other  two 
cylinders,  that  is  cylinders  2  and  3.  It  should  be  noted  that  while  these  direc- 
tions will  care  for  the  average  four-cylinder  engine,  experiments  will  show  the 
best  timing.  Frequently,  instructions  for  timing  the  magneto  to  a  particular 
engine  are  available.  In  this  case  they  should  be  followed  as  closely  as  pos- 
sible. 

Attaching  Cables  to  Brush  Holders. — The  brush  holders  fit  into  plates  in 
each  side  of  the  driving  shaft  end  plate,  being  held  in  place  by  the  L  plate 
catch   springs.     These   springs   are  pivoted   at   one   end,   and  at   the    other,   or 

rounded  end,  carry  a  small  boss  which, 
when  in  position,  rests  in  a  notch  in 
the  brush  holder  and  secures  the  holder 
in  place.  A  slight  downward  pressure 
and  outward  pull  of  the  rounded  end  of 
the  spring  disengages  the  spring  and 
permits  the  removal  of  the  brush 
holder. 


To  connect  the  spark  plug  cables 
to  the  magneto  the  brush  holder^  are 
removed  and  the  brushes  withdrawn. 
At  the  base  of  each  of  the  brush  recep- 
tacles is  a  pointed  cable  fastening 
screw.  Remove  this  with  a  narrow 
bladed  screw  driver.  Do  not  force  a 
large  blade  into  the  insulator  or  it 
will  be  cracked  or  broken.  Next  in- 
sert the  cable  end.  This  is  cut  off 
square   and   the   end   has   no   insulation 

removed.     Replace  the  screws.     As  they  are  turned  in  they  pierce  the  cable 

and  make  perfect  electrical  contact  while  securing  it. 

Troubles  and  Remedies. — The  instruction  given  with  reference  to  the  DU 

types  applies  equally  as  well  to  the  NU  type. 


Fig.  470. 


Bosch  High  Tension  Magneto 
Type   "NU4". 


JOB  140.     BOSCH  DUAL  IGNITION  SYSTEMS. 

Dual  ignition  means  not  two  independent  sets  of  ignition  equipment,  but 
rather  two  independent  sources  of  current.  The  one  set  of  plugs,  and  certain 
other  parts  as  the  distributor  and  cables,  are  used  for  the  application  of  the 
current  from  either  source  to  work  or  duty  of  igniting  the  charge  of  fuel  within 
the  cylinder. 

The  Bosch  Dual  Magneto  is  of  the  armature  type  common  to  all  Bosch 
instruments.  It  produces  its  own  current  and  times  it  through  the  interrupter 
points   and   breaker   mechanism.     As   in    the    independent    types,    the    breaker 


Magneto  Ignition 


401 


points  are  carried  on  a  disk  which  is  attached  to  the  armature  shaft.  The 
segments  which  serve  as  cams  to  break  the  points  are  attached  to  the  housing 
in  the  usual  Bosch  design. 

In  addition  the  dual  magneto  is  provided  with  a  steel  cam  having  two 
projections  which  is  built  into  the  interrupter  disk.  This  cam  acts  on  a  lever 
that  is  supported  on  the  interrupter  housing,  the  lever  being  so  connected  in 
the  battery  circuit  that  it  serves  as  a  timer  to  control  the  flow  of  the  battery 
current  through  the  coil.     These  parts  are  illustrated  in  Fig.  473. 

Battery  Current  Units. — The  student  is  familiar  with  the  fact  that  when 
battery  current  is  used  in  conjunction  with  the  high  tension  magneto,  the 
purpose  is  always  to  give  easy  starting.  All  induced  current  in  any  ignition 
system  being  dependent  upon  the  rapidity  with  which  the  lines  of  force  are  cut 
by  the  winding  or  vice  versa,  it  has  been  found  impractical  under  certain 
conditions  to  secure  a  fast  or  high  enough  cranking  speed  to  enable  the 
operator  to  start  the  engine  on  magneto,     Since  the  battery  current  is  avail- 


Fig.  471. 

able  at  a  uniform  voltage  it  is  used  to  give  the  initial  current  for  starting.  All 
units  needed  for  battery  ignition  are  required.  All  units  required  for  the 
independent  magneto  operation  are  needed  for  running.  The  distributor  cables 
and  spark  plugs  are  made  use  of  for  both  systems. 

It  is  obvious  that  the  sparking  current  from  the  battery  and  from  the 
magneto  cannot  be  led  to  the  spark  plugs  at  the  same  time.  A  further  change 
from  the  magneto  of  the  independent  form  is  found  in  the  removal  of  the 
conducting  bar  between  the  collecting  ring  brush  and  the  distributor  center. 
Instead,  the  high  tension  current  is  led  to  the  switch,  and  a  second  cable 
conducts  the  current  from  the  switch  to  a  terminal  connecting  with  the 
distributor  center. 

When  operating  on  the  magneto,  the  sparking  or  high  tension  current 
flows  through  the  switch  to  the  distributor.  When  running  on  battery  the 
primary  circuit  of  the  magneto  is  grounded,  consequently  no  high  tension 
current  is  generated.  It  is  then  that  the  high  tension  current  from  the  coil 
is  led  to  the  spark  plugs.  This  current  is  led  from  the  coil  to  the  center  of  the 
distributor  on  the  magneto. 

Bosch  Synchronous  Coil. — This  is  illustrated  in  detail  in  Fig.  474.  The 
coil  consists  of  a  cylindrical  housing  bearing  a  brass  casting  which  serves  as  a 
mounting  flange.     When  the  engine  is   running  on  battery  ignition,  a  single 


402 


Automotive  Trade  Training 


high  tension  spark  occurs  at  the  moment  the  contacts  separate.  The  intensity 
of  this  spark,  as  well  as  its  accurate  timing,  permits  of  operating  the  engine 
on  battery  current. 

Switch. — The  end  plate  of  the  housing  carries  the  switch  handle.  The 
switch  mechanism  is  built  integral  with  the  coil.  By  means  of  the  switch 
either  the  magneto  or  the  battery  may  be  employed  as  the  source  of  ignition 
current.  In  operating  the  switch  the  entire  coil  is  rotated  within  the  coil 
housing.  The  inner  side  of  the  stationary  switch  plate  is  provided  with  spring 
contacts  that  register  with  the  contact  plates  attached  to  the  base  of  the  coil. 

Independence  of  the  Systems. — While  the  prime  feature  of  the  dual  system 
is  the  ability  to  start  the  engine  at  slow  cranking  speeds,  it  is  a  reliable  system 
for  running  in  case  of  failure  of  some  part  of  the  magneto.  Each  system 
utilizes  the  distributor  in  common.  This  is  a  part  seldom  causing  trouble  or 
failing  for  any  reason. 

Push  Button  Starting  Feature. — For  the  purpose  of  starting  on  the  spark, 
a  vibrator  may  be  cut  into  the  coil  circuit  by  pressing  the  button  which  may 
be  seen  in  the  center  of  the  end  plate  of  Fig.  474.  Normally  this  vibrator  is  out 
of  circuit,  but  the  pressing  of  the  button  brings  together  its  platinum  points 
and  a  vibrator  spark  of  high  frequency  is  produced.  If  a  cylinder  on  the  power 
stroke  is  provided  with  an  unexploded  charge  of  fuel,  pressing  of  the  button 
will  give  the  needed  spark  to  ignite  it  and  thus  start  the  engine. 

Wiring  the  Dual  System. — Refer  to  Fig.  472.  It  will  be  noted  that  while 
the  independent  magneto  requires  but  one  switch  wire  in  addition  to  the  spark 
plug  cables,  the  dual  system  requires  four  connections  between  the  magneto 
and  the  switch.  Two  of  these  are  high  tension  and  consist  of  wire  No.  3  by 
which  the  high  tension  current  from  the  magneto  is  led  to  the  switch  contact, 
and  wire  No.  4  by  which  the  high  tension  current  from  either  the  magneto  or 
coil  is  conducted  to  the  terminal  in  the  center  of  the  distributor.     Wire  No.  1 


16 

■Ground 


Outton. 


Batfary 

Secondary   to  Oist 
Mag  See.  to  Snitch. 
Mag  Grounding  tVira 
Battery  Circuit  Bncktr 


^ 


Fig.  472.    Wiring  Diagram  of  the  "DU4"  Dual  System. 
(On  Magnetos  of  the  Model  4  class,  the  grounding  terminal  is  located  on  the  side  of  the 

circuit  breaker  housing. 


Magneto  Ignition  403 

is  low  tension  being  used  to  carry  the  battery  current  from  the  primary 
winding  of  the  coil  to  the  battery,  interrupter.  Low  tension  wire  No.  3  is  the 
grounding  wire  by  which  the  primary  circuit  of  the  magneto  is  grounded. 
This  occurs  when  the  switch  is  thrown  to  the  off  or  the  battery  position.  Wire 
No.  5  leads  from  the  negative  terminal  of  the  battery  to  the  coil.  Wire  No.  7 
is  used  to  ground  the  positive  terminal  of  the  battery.  A  second  ground  wire 
No.  6  is  used  to  ground  the  coil  terminal. 

Setting  the  DU  Dual  Magneto. — The  Dual  magneto  is  so  arranged  that  the 
battery  interrupter  breaks  its  circuit  at  approximately  ten  degrees  later  than 
the  magneto  interrupter.  This  feature  gives  the  full  timing  range  of  the 
magneto.  With  the  timing  lever  fully  retarded  and  the  switch  on  the  battery 
position,  the  battery  spark  will  occur  after  the  piston  has  reached  and  passed 
top  dead  center  and  is  moving  downward  on  the  power  stroke.  This  feature 
eliminates  the  danger  of  backfire. 

Timing  the  Dual  Magneto. to  the  Engine. — The  process  is  similar  to  that 
for  the  independent  type.  The  magneto  should  be  placed  in  position  on  the 
bed  plate  or  pad  provided  for  it,  the  bolts  and  straps  being  properly  secured. 
The  driving  gear  or  coupling,  however,  should  be  left  loose  on  the  driving 
shaft.  The  instructions  given  in  Job  136  for  timing  the  independent  type  may 
be  followed,  or  the  following  method  may  be  used  which  will  give  the  same 
result. 

First  remove  the  aluminum  dust  plate  which  is  located  under  the  arch  of 
the  magnets  and  over  the  armature.  To  remove  this  it  will  be  necessary  to 
note  if  spring  catches  or  screws  are  used  to  secure  it  in  position.  If  spring 
clips  are  used  a  screw  driver  may  be  used  to  spring  the  cover.  The  greatest 
care  should  be  used  to  see  that  no  foreign  materials  such  as  screws  or  washers 
are  dropped  into  the  armature  tunnel  while  the  dust  cover  is  off.  Next,  crank 
the  engine  until  the  piston  in  cylinder  No.  1  is  on  top  dead  center,  compression 
stroke.  The  armature  should  now  be  rotated  in  the  direction  it  will  turn, 
clockwise  or  anti-clockwise  until,  in  the  position  shown  in  Fig.  471.  The 
correct  setting  for  the  armature  is  determined  by  the  dimension  marked  "e". 
For  the  DU4  this  should  be  from  10  to  15  millimeters.  For  the  DU6  the  setting 
should  be  from  12  to  20  millimeters.  These  -settings  represent  an  advance  of 
from  10  to  15  millimeters  on  motors  with  130  millimeters  stroke. 

With  the  armature  held  in  this  position  and  the  crank  shaft  and  pistons 
as  placed,  the  magneto  coupling  may  be  secured.  It  is  difficult  to  give  the 
exact  setting.  This  is  often  determined  by  experiment  after  the  approximate 
setting  has  been  found  as  above. 

Setting  the  ZR  Dual  Magneto. — In  this  case  it  is  unnecessary  to  remove 
either  the  interrupter  housing  cover  or  the  distributor  plate  in  order  to  deter- 
mine the  setting  of  the  instrument,  or  to  locate  the  distributor  terminal  with 
which  contact  is  being  made.  First  fasten  the  magneto  in  position  allowing 
the  coupling  to  remain  loose.  Bring  piston  No.  1  to  firing  position  for  full 
advance.  The  fly  wheel  markings,  or  the  engine  manufacturer's  instruction 
book  may  give  this.  Next  rotate  the  armature  until  the  Fig.  1  can  be  seen 
through  the  window  in  the  face  of  the  distributor  plate.  The  cover  of  the  oil 
"well  on  the  distributor  end  of  the  magneto  is  then  to  be  raised  and  the  armature 
is  to  be  rotated  a  few  degrees  in  either  direction-  until  the  red  mark  on  one  of 
the  distributor  gear  teeth  is  brought  into  register  with  the  red  marks  on  the 
side  of  the  window  located  between  the  two  oil  ducts.  The  magneto  is  then 
in  time  for  the  full  advance  position,  and  since  the  engine  has  been  maintained 
in  that  position  the  two  may  be  connected. 

Dual  Coil  Care  and  Use. — When  a  four-cylinder  engine  comes  to  a  stop 
it  is  very  likely  to  stop  with  the  crank  shaft  in  a  horizontal  position.     The 


404 


Automotive  Trade  Training 


■ 

g 

— ^ --! 

^  Lock  nut 

^  Contact  block 

^  Segment 

Fastening  screw  to. 

[^ppv 

|^^hji^\j0^^^n 

^  Long  platinum  screw 

Contact  block    -^ 

Wri 

r^V^ufl 

,^  Fastening  screw  for  spring    • 
>- Short  platinum  screw 

nbre  block  ^, 

Segment,^ 

lim 

"  x'^^^^^^  \ 

>^  Interrupter    lever 

Auxiliary  sprinu  ^ 

0km 

ft'^'-^fcs 

iZP*'  ^HK  m^ 

>-  Auxiliary  spring 

Short   platinum    :    ■  . 

"       J^ 

^1 

z!^i0^SWm  1^^ 

^        ^    Spring  |5ost 

Long    platinum   serf.-.-  ^ 

^1 

|V<jy^nj^v^^^^| 

^k^^  ^  Fastening  screw  for  spring 

Lock  nut  -<  —    . 

M^^ 

^^ 

^■r^^'-<  Screw  plate 

Terminal  stud  _, 

Md     vi 

!l^ 

i^^ln 

^^sPv^B^I 

HBHr-*- Spring  for  magneto  interrupter 

Terminal  plate -^. 

■F^Ll 

Wf^ 

^Z 

^^g^jf^j^^l 

^HgR-^ Spring  for  tiattery  interrupter 

Insulating  plate  .^ 

£" 

!^fi 

ssSHPi^P 

"*•«-    /j^  Interrupter  fastening  5Crew 

Insulating   plate  — « 

*- «. 

^^^^ 

IJJPHr^ 

_  Screw  plate 

k 

-- 

F\s.   473.     InterruiJter   and    Battery    Timer   for   Type   "ZIU"   Dual. 


pistons  are  at  the  midpoint  of  their  stroke.  At  this  position  of  the  crank  shaft 
the  battery  contact  points  are  open.  As  the  battery  interrupter  and  coil 
vibrator  are  in  parallel,  a  pressure  on  the  starting  button  of  the  coil  will  close 
the  battery  circuit  through  the  battery  and  primary  winding  of  the  coil.  As 
this  current  is  broken,  the  high  tension  spark  is  induced  in  the  usual  manner. 
The  distributor  brush  at  that  instant  will  be  in  contact  with  the  distributor 
terminal  which  is  in  connection  with  the  spark  plug  in  the  cylinder  on  the 
firing  stroke.  The  ignition  of  the  charge  within  this  cylinder  will  follow. 
If,  for  any  reason,  the  engine  comes  to  a  stop  with  the  pistons  on  the 
end  of  their  strokes,  the  push  button  starting  will  not  be  possible  since 
the  primary  circuit  is  already  in  the  circuit  through  the  battery  interrupter, 
and  no  break  of  this  primary  circuit  can  be  effected.  Consequently  no  high 
tension  current  can  be  induced. 

Vibrating  Coil  and  Plain  Coil  Combined. — For  ordinary  starting  conditions 
the  push  button  should  be  set  to  the  position  marked  "Run".  This  will'give  a 
single  hot  jump  spark  similar  to  that  common  to  standard  battery  ignition. 
This  spark  is  dependent  on  the  break  of  the  battery  interrupter  points.  How- 
ever, if  difficulty  is  experienced  in  starting,  the  vibrator  may  be  used  to  secure 
a  shower  of  sparks  similar  to  the  vibrating  coil  described  in  Chapter  11.  To 
utilize  this  feature  of  the  coil  the  push  button  should  be  pushed  down  or  in, 
and  then  turned  to  the  right  to  the  "Start"  position.  This  locks  the  vibrator 
in  circuit  and  a  shower  of  sparks  is  produced  instead  of  the  single  one.  This 
method  should  be  used  only  for  starting  on  a  poor  mixture  or  when  the  motor 
is  cold. 

Battery. — The  standard  dual  coils  are  wound  for  a  battery  current  of  six 
volts.  Either  storage  or  dry  cells  may  be  used.  Each  coil  is  wound  for  a 
certain  voltage,  and  if  this  is  not  exceeded  the  platinum  points  will  not  require 
much  attention.  This  voltage  is  stamped  on  the  coil.  If  dry  cells  are  used 
the  number  should  be  ten  for  the  four-cylinder  engines  and  twelve  for  the 
six-cylinder  engines.  Multiple  series  connections  should  be  used,  having  two 
groups  of  five  or  six  cells  in  each  group. 

Detecting  General  Trouble  in  Ignition  System. — In  the  event  of  failure  of 
the  ignition  system  it  should  first  be  determined  which  side  of  the  system  is 
at  fault.  It  may  be  both.  This  may  be  determined  by  throwing  the  switch 
from  one  side  to  the  other.  If  there  is  a  continual  miss  on  one  cylinder  on  the 
magneto  as  well  as  the  battery,  the  fault  usually  lies  in  the  spark  plug.  This 
will  likely  be  due  to  fouling,  breaking,  or  improper  gap.  If  a  failure  is  found 
in  all  cylinders  on  the  battery  as  well  as  on  the  magneto,  the  fault  is  due  to  a 


Magneto  Ignition 


405 


short  circuit  due  to  failure  of  insulation  of  the  cables,  to  improper  contact,  or 
to  the  grounding  of  the  terminals.  This  fault  may  also  be  due  to  broken  cables. 
High  tension  cables  Nos.  3  and  4  should  be  tested. 

Detecting  Dual  Magneto  Trouble. — If  the  switch  shows  the  magneto  to  be 
the  side  at  fault,  all  cables  and  terminals  should  be  examined  for  poor  or 
wrong  connections.  The  coil  and  battery  system  may  then  be  disconnected  by 
removing  the  wires  from  terminals  Nos.  3  and  4  of  the  magneto,  and  connecting 
3  directly  to  4  with  a  short  piece  of  wire.  This  will  conduct  the  high  tension 
current  from  the  collector  ring  to  the  center  of  the  distributor.  Next, 
disconnect  the  grounding  wire  from  terminal  No.  2  of  the  magneto.  With  this 
arrangement  it  should  be  possible  to  start  the  engine  on  the  magneto.  If 
something  has  happened  to  the  coil  this  method  must  be  resorted  to. 


Fig.   474.     Parts   of  the   Coil. 


To  ascertain  if  the  magneto  is  generating  current,  the  wire  shoula  be 
disconnected  from  terminal  No.  2  on  the  magneto.  Next  disconnect  the  high 
tension  wire  No.  3  from  the  collecting  ring  terminal.  If  the  engine  is  then 
cranked  briskly  the  magneto  should  show  a  spark  at  the  safety  spark  gap 
located  under  the  arch  of  the  magnets  on  the  dust  cover.  If  no  spark  is  shown 
at  the  safety  spark  gap  the  trouble  may  be  a  leakage  or  loss  of  the  low  tension 
current.  This  might  be  caused  by  chafed  insulation,  incorrect  connections,  or 
an  injury  to  the  switch  parts. 

Detecting  Battery  System  Faults. — If  the  engine  misses  on  the  battery  but 
operates  well  on  the  magneto  the  fault  will  usually  be  found  within  the  battery 
itself,  the  voltage  having  dropped  too  low.  Should  the  battery  show  the  proper 
voltage,  the  battery  interrupter  should  be  examined  to  observe  whether  the 
lever  moves  freely.  The  points  also  must  be  clean  and  properly  adjusted. 
These  points  are  kept  just  a  trifle  wider  than  the  magneto  interrupter  points. 

The  coil  should  not  be  dismounted  unless  this  is  first  found  by  tests  to  be 
absolutely  necessary.  To  test  the  coil  first  disconnect  wire  No.  4  from  the 
magneto  and  throw  the  switch  to  the  battery  position.  Hold  the  terminal  on 
the  end  of  wire  No.  4  a  slight  distance  from  the  engine  or  some  other  metal 
ground  and  operate  the  push  button.  A  brilliant  jump  spark  will  be  seen  if 
the  coil  is  in  good  condition.  If  the  spark  does  not  appear,  repeat  the  test 
with  wire  No.  3  disconnected.  Failing  to  get  a  spark  under  this  test  it  may  be 
necessary  to  remove  the  coil.  To  do  this,  first  remove  the  holding  screw  which 
is  located  close  to  the  supporting  flange.  The  switch  should  then  be  unlocked 
and  the  end  plate  given  a  quarter  revolution.     This  will  release  the  bayonet 


406  Automotive  Trade  Training 

lock  and  the  coil  body  may  then  be  withdrawn  to  permit  the  inspection  of  the 
switch  contacts  both  of  the  coil  and  the  stationary  switch  plate.  It  is  possible 
that  the  spring  contacts  are  bent  or  otherwise  in  bad  condition.  The  with- 
drawing and  subsequent  handling  should  be  performed  with  extreme  care. 
Further  tests  for  ignition  coils  are  given  elsewhere. 

JOB  141.     BOSCH  DUPLEX  IGNITION  SYSTEM. 

The  Bosch  Duplex  Ignition  System  is  so  designed  as  to  offer  a  simple 
method  of  starting  the  engine  at  low  cranking  speeds.  A  battery  is  used  in 
conjunction  with  the  Duplex  Ignition  Coil  and  a  standard  high  tension  magneto 
arranged  for  duplex  ignition.  When  so  arranged  the  magneto  is  known  as  a 
duplex  magneto.  The  duplex  coil  is  low  tension  only.  The  same  set  of  plugs 
is  used  for  both  the  battery  ignition  and  the  magneto  ignition.  The  magneto 
circuit  is  complete  within  itself.  The  battery  side  includes  the  battery  and 
coil  in  circuit  with  the  low  tension  winding  of  the  armature.  The  battery  side 
is  not  intended  to  be  used  as  separate  ignition  but  merely  as  an  auxiliary  to 
the  magneto  to  insure  easy  starting  at  slow  cranking  speeds. 

Operation  of  Battery. — Under  this  condition  the  switch  is  so  arranged  in 
conjunction  with  the  wiring  of  the  magneto  as  to  include  the  low  tension  or 
primary  winding  of  the  magneto  in  circuit  with  the  duplex  coil.  The  action 
of  the  battery  is  to  supplement  the  normal  action  of  the  magneto  which,  at 
extremely  slow  speeds,  does  not  generate  enough  current  to  induce  a  high 
tension  spark  when  the  breaker  points  are  opened. 

Since  the  magneto  generates  an  alternating  current  which  changes  its 
direction  of  flow  every  180  degrees  revolution  of  the  armature,  some  changes 
from  the  independent  high  tension  type  magneto  are  necessary.  While  the 
battery  current  is  direct  current,  to  be  held  in  phase,  (meaning  to  act  or  flow 
with),  with  the  magneto  current  it  is  necessary  to  provide  a  commutator  on 
the  magneto.  To  this  end  a  simple  form  of  commutator  is  fitted  on  the  inner 
surface  of  the  interrupter  housing  cover.  The  commutator  is  not  desig^ied  to 
change  the  direction  of  flow  of  magneto  current,  but  rather  to  change  the 
direction  the  battery  current  flows  through  the  armature  low  tension  winding. 
This  causes  the  battery  current  always  to  flow  in  the  direction  of  the  current 
being  generated  within  the  magneto.  Each  current,  battery  and  magneto,  then 
change  the  direction  of  flow  each  half  revolution  of  the  armature.  With  the 
starting  of  the  engine,  and  at  the  lowest  speeds  at  which  it  is  possible  to 
operate  the  engine,  the  magneto  will  generate  enough  current  within  the 
primary  winding  to  induce  current  within  the  secondary  winding  for  the  high 
tension  spark.  After  the  engine  has  started,  the  ignition  is  equally  efficient 
whether  the  switch  is  left  on  the  battery  side  or  turned  over  to  magneto. 
However,  in  order  to  reduce  the  drain  on  the  battery  it  is  best  to  throw  the 
switch  to  magneto  immediately  the  engine  has  started. 

Operation  on  Magneto. — When  the  switch  is  thrown  to  magneto  position, 
the  battery  connection  is  interrupted,  and  the  operation  of  the  magneto  is 
identical  in  every  way  with  the  operation  of  an  independent  magneto.  It 
should  be  noted  that  the  battery  and  duplex  coil  are  employed  in  the  battery 
circuit  only  and  not  in  the  magneto  circuit.  The  removal  of  either  the  battery 
or  coil  would  interfere  not  at  all  with  the  operation  of  the  engine  on  magneto, 
but  the  difficulty  is  in  starting  at  slow  cranking  speeds  directly  on  the  magneto. 

Bosch  Duplex  Magneto. — Aside  from  the  interrupter  and  interrupter 
housing  described  herewith,  the  construction  of  the  duplex  magneto  is  identical 
with  the  corresponding  independent  high  tension  types. 

The  interrupter  housing  consists  of  a  fiber  disk  which  is  maintained  in 


Magneto  Ignition 


407 


fixed  relation  to  the  housing  by  a  key  fitted  into  a  keyway.  The  inner  surface 
of  the  disk  is  provided  with  two  metal  segments  as  shown  in  Fig.  475.  Each 
of  these  segments  has  an  external  terminal  for  connecting  it  in  circuit.  The 
interrupter  is  provided  with  two  brushes  which  make  contact  with  the  metal 


.  tNTERRUPTe.R  POINT 
^CARBON  BRUSH  A 


CAPDON BRUSH  B-j- 


COMMUTATOfi^SEGMENTS  "'•*''''°  CONTROL'^ 

Fig.  475.     "DU4"  Duplex  Magneto  partly  disassembled. 

segments  on  the  cover  as  the  armature  is  turned.  These  two  brushes  together 
with  the  commutator  might  be  compared  with  the  Simple  Direct  Current  Motor 
shown  in  Fig.  278.  However,  in  this  case  the  commutator  serves  to  convert 
D.  C.  current  into  A.  C.  current  instead  of  A.  C.  to  D.  C.  as  in  the  illustration. 
The  reversal  thus  provided  for  is  necessary  to  hold  the  battery  current  in 
phase  with  the  magneto  current,  as  indicated  previously. 

Switch  and  Coil. — These  units  are  built  together.  The  coil  is  a  simple 
primary  winding.  It  is  fitted  with  a  push  button  and  vibrator  points  for  push 
button  starting.  The  coil  is  not  likely  to  give  any  trouble,  in  case  of  the 
removal  of  any  connections,  care  must  be  used  to  have  them  replaced  correctly. 
If  the  battery  is  so  connected  to  the  coil  and  magneto  that  the  two  currents 
are  not  in  phase,  they  will  buck  one  another  as  soon  as  the  engine  is  started 
and  the  magneto  primary  winding  starts  generating  its  own  current.  This 
will  result  in  stopping  the  motor.  To  correct  this  trouble  which  is  evidenced 
by  the  engine  stopping  almost  immediately  it  is  started,  it  is  only  necessary  to 
put  the  two  currents  in  phase  by  changing  the  battery  wires  either  at  the  coil 
or  at  the  battery, 


JOB  142.     BOSCH  VIBRATING  DUPLEX  IGNITION. 

The  Vibrating  Duplex  Ignition  System  is  designed  to  reduce  to  a  minimum 
the  effort  required  to  start  magneto  equipped  engines.  The  complete  ignition  sys- 
tem operates  on  one  set  of  plugs.     It  consists  of  a  standard  high  tension  magneto, 


408 


Automotive  Trade  Training 


a  low  tension  vibrating  coil,  and  a 
control  switch  together  with  the 
battery  and  necessary  wiring. 

Magneto. — The  standard  Bosch 
Independent  High  Tension  mag- 
netos are  used.  These  are  described 
in  Job  Sheets  Nos.  136,  137,  and  138. 
Any  questions  arising  concerning 
their  care,  operation  and  timing  are 
cared  for  under  these  headings.  The 
construction,  care  and  use  of  the  du- 
plex vibrating  coil  are  treated  in 
this  job  sheet. 

Vibrating  Duplex  Coil  Con- 
struction. —  The  vibrating  duplex 
coils  are  known  as  type  VD  Ed.  1 
and  type  VD  Ed.  2.  The  housing 
is  in  two  parts,  the  base  part  so 
arranged  that  it  may  be  held  in  posi- 
tion on  the  dash  or  floor  board,  the 
other  so  arranged  as  to  permit  its 
being  removed  to  adjust  or  inspect 
the  coil  proper.  This  construction 
completely  housing  as  it  does  all 
parts,  protects  them  from  injury 
and  prevents  dirt,  grease,  etc.,  from 
entering  to  make  trouble.  The 
flanged  section  of  the  housing  carries 
the  coil  base  which  is  of  insulating 
material.  The  iron  core  of  the  coil  is  H  shaped  and  is  mounted  on  the  base. 
The  insulated  wire  forming  the  winding  is  wound  about  the  H  core.  One  end 
of  the  wire  is  grounded  onto  the  core,  while  the  other  end  is  connected  to  one 
of  the  two  outside  terminals  of  the  coil. 

VD  Ed.  1  Coil. — In  this  case  the  iron  core  is  threaded  at  its  upper  end 
to  receive  the  vibrator  cover,  the  closed  end  of  which  carries  the  insulated 
adjustable  vibrator  screw,  with  a  platinum  contact  projecting  on  the  inside  of 
the  cover.  A  second  vibrator  contact  is  mounted  on  one  side  of  a  wide,  flat 
spring,  the  other  side  of  which  carries  a  soft  iron  button.  This  arrangement 
constituting  the  vibrator  assembly  is  mounted  on  the  inside  of  the  vibrator 
cover  in  such  a  way  that  the  soft  iron  button  faces  the  coil  winding  and  the  two 
vibrator  contacts  meet.  The  adjustable  vibrator  screw  is  connected  by  means 
of  a  short  wire  to  the  second  outside  coil  terminal. 

VD  Ed.  2  Coil. — In  this  type  the  vibrator  cover  is  not  used.  The  vibrator, 
consisting  of  the  vibrator  spring,  platinum  contact  and  soft  iron  trembler 
button,  is  mounted  upon  and  supported  above  the  pole  shoes  in  such  a  way 
that  its  platinum  contact  is  in  contact  with  the  platinum  of  the  adjustable 
vibrator  screw.  The  screw  in  this  case  is  carried  by  a  bridge  mounted  above 
the  pole  shoes.  This  is  shown  in  Fig.  477.  As  in  the  other  type  the  adjust- 
able contact  screw  is  connected  to  the  second  outside  terminal  screw. 

Condenser. — In  order  to  reduce  the  wear  on  the  platinum  contact  points 
and  to  produce  the  further  proper  action  of  the  coil,  a  condenser  is  provided. 
The  action  of  the  condenser  is  described  in  Chapter  10  and  again  in  Chapter  12. 
The  condenser  is  mounted  on  the  iron  core  of  the  coil  opposite  the  base. 

Principle  of  Coil  Operation. — The  battery  current,  upon  reaching  the  coil 
terminal  with  which  the  coil  winding  is  connected,  passes  through  the  winding 


Fig.     476. 


Bosch    Vibrating    Duplex    Coil, 
VD    Ed.    1. 


Magneto  Ignition 


409 


to  the  iron  core,  thence  to  the   flat  vibrator  spring  with  its  contact,  then  to 
the  adjustable  vibrator  screw,  and  finally  out  of  the  coil  by  the  second  terminal. 

When  the  complete  battery  cir- 
cuit is  established,  the  coil  winding 
by  reason  of  the  current  passing 
through,  acts  as  an  electromagnet, 
alternately  attracting  the  iron  but- 
ton on  the  flat  vibrator  spring.  The 
first  action  interrupts  the  battery 
current  and  the  second  re-establishes 
it.  These  actions  follow  each  other 
in  such  rapid  succession  that  they 
give  rise  to  a  continuous  vibration 
or  buzz  which  lasts  as  long  as  the 
switch  is  in  battery  position. 

The  coil  is  so  constructed  that 
it  may  be  used  in  conjunction  with 
circuits  of  from  six  to  sixteen  volts. 
This  permits  of  the  coil  being  used 
on  any  of  the  batteries  ordinarily 
employed  for  starting  and  lighting 
service. 

Wiring  Directions.  —  Refer  to 
Figs.  478  and  479  for  the  wiring  dia- 
grams. It  should  be  observed  that 
all  cables  excepting  the  spark  plug 
wires  are  primary  or  low  tension 
wires.  Where  the  coil  is  used  with 
the  two-wire  or  insulated  return 
system  the  connections  for  the 
type  Sl7  switch  should  be  in 
accordance  with  the  wiring  diagram  shown  in  Fig.  479.  One  low  tension  cable 
from  the  negative  battery  terminal  is  run  to  one  terminal  of  the  vibrating  coil. 
A  second  low  tension  cable  is  run  from  the  other  coil  terminal  to  the  switch 
terminal  marked  "Coil."  A  third  low  tension  cable  is  run  from  Mag.  on  the 
switch  to  the  grounding  terminal  on  the  magneto  interrupter  housing.  A 
fourth  one  is  run  from  the  switch  terminal  marked  Grd.  to  a  grounding  point 


Fig.     477. 


Bosch    Vibrating 
VD    Ed.    2. 


Duplex    Coil, 


No.  1. 

Arrangement  when  employing 
battery  of  an  insulated  return 
lighting  or  starting  system. 


Fig. 


VD   Coil  Wiring  Diagram. 


410 


Automotive  Trade  Training 


?^^3 


I    tttrtrt 


No.  2. 

Arrangement  when  employing 
battery  of  a  eround  return 
lighting  or  starting  system,  or 
separate  battery  for  ignition. 


Fig.  479.     VD   Coil  Wiring  Diagram. 

on  the  engine  or  car  frame.     The  fifth  and  final  cable  is  run  from  the  switch 
terminal  Bat.  to  the  positive  terminal  of  the  battery. 

Where  the  system  is  used  with  a  single  wire,  or  ground  return  starting 
and  lighting  system,  or  where  the  battery  is  used  solely  for  ignition,  the  switch 
and  battery  connections  will  be  the  same  as  for  a  two-wire  system  with  one 
exception.  The  positive  terminal  of  the  battery  is  to  be  grounded  while  the 
terminal  marked  Bat.  in  back  of  the  switch  is  to  be  left  free.  The  complete 
connections  for  this  arrangement  are  shown  in  the  wiring  diagram  Fig.  478. 

Operation  of  System  on  Battery. — The  primary  circuit  of  the  magneto  is 
included  in  the  battery  circuit.  This  is  in  series  with  the  battery  and  the  coil. 
The  purpose  of  the  battery  is  to  supplement  the  current  generated  within  the 
magneto  at  slow  cranking  speeds. 

With  the  switch  in  the  battery  position,  current  from  the  battery  passes 
through  the  vibrating  coil  to  the  insulated  magneto  grounding  terminal,  the 
inner  end  of  which  is  in  contact  with  the  head  of  the  magneto  interrupter 
fastening  screw.  The  interrupter  fastening  screw,  in  turn,  is  connected  with 
the  end  of  the  armature  primary  circuit,  so  that  when  the  magneto  interrupter 

contacts  are  open,  the  battery  current 

passes  through  the  armature  primary 
circuit  to  its  beginning  or  grounded 
end,  thence  returning  to  the  battery 
through  the  ground.  When  the  mag- 
neto interrupter  contacts  are  closed, 
however,  the  current  from  the  battery, 
after  reaching  the  interrupter  fastening 
screw,  passes  to  the  interrupter  contact 
block,  then  across  the  magneto  inter- 
rupter contacts  to  ground,  thus  com- 
pleting the  circuit  to  the  battery  with- 
out passing  through  the  magneto 
armature  primary  circuit.  When  the 
switch  is  in  the  battery  position,  each 
separation  of  the  magneto  contact 
interrupter  points  throws  the  current 
from  the  battery  and  vibrating  coil  into 
the  primary  circuit  of  the  magneto 
armature,  thereby  supplementing  the  current  generated  within  the  magneto 
through  the  rotation  of  the  armature  in  the  magnetic  field.     This  induces  in 


Fig.  480.     Bosch   Switch. 


Magneto  Ignition  411 

the  secondary  circuit  of  the  magneto  armature  a  very  high  tension  sparking 
current.  This  sparking  current  on  account  of  the  action  of  the  coil  appears 
not  as  a  single  spark  but  a  series  of  intense  sparks.  The  student  will  readily 
see  the  benefits  derived  from  having  this  intense  shower  of  sparks  flowing 
between  the  spark  plug  points  when  the  engine  is  being  cranked  over  slowly. 
With  a  mixture  anywhere  near  correct  the  engine  is  almost  certain  to  be 
started.  The  sparking,  or  high  tension  current,  is  distributed  in  the  usual  way 
through  the  magneto  distributor.  The  battery  side  is  not  intended  as  a 
separate  ignition  system. 

Coil  Care  eind  Adjustment. — The  only  parts  of  the  coil  subject  to  wear 
are  the  platinum  vibrator  contacts.  First  remove  the  coil  cap.  Next  loosen 
the  hexagon  lock  nut  and  then  slightly  advance  the  contact  point  on  the 
adjustable  screw  by  screwing  in  on  it.  This  brings  the  platinum  points  into 
contact  with  each  other  and  compensates  for  any  wear  which  may  have 
occurred.  This  adjustment  need  be  made  only  once  or  twice  a  season  at  the 
most.  After  considerable  service  it  may  be  necessary  to  remove  the  screws 
and  points  for  inspection  and  repair.  To  put  them  back  in  condition  a  very 
fine  jeweler's  or  platinum  point  file  is  used.  Other  than  this  the  coil  requires 
no  care.  In  case  of  serious  trouble  it  may  be  tested  as  indicated  for  coil  tests. 
Chapter  12. 

Troubles,  Cause  and  Remedy. — Since  the  coil  is  made  to  operate  in  con- 
junction with  the  magneto,  faults  due  to  the  magneto  will  appear  on  the  battery 
side  as  well  as  the  magneto  side  of  the  system.  When  testing  for  troubles  it 
is  always  well  to  start  and  operate  the  engine  on  the  magneto  side  independent 
of  the  battery  side,  if  that  is  possible.  To  make  this  test  independent  of  the 
coil,  it  is  necessary  only  to  remove  the  low  tension  wire  leading  from  the 
battery  to  the  coil.  Refer  to  the  jobs  covering  Bosch  High  Tension  Magnetos 
for  a  digest  of  magneto  troubles. 

So  far  as  the  battery  side  is  concerned  there  is  very  little  to  get  out  of 
order.  Practically  the  only  parts  likely  to  get  out  of  order  are  the  platinum 
points  and  these  are  so  protected  by  the  condenser  action  that  they  require 
attention  at  infrequent  intervals. 

Failure  of  Coil  to  Vibrate. — If,  with  the  switch  on  the  battery  side,  the 
coil  fails  to  vibrate  when  the  switch  is  in  battery  position  the  first  unit  to 
suspect  of  failure  is  the  battery.  The  voltage  may  have  dropped  to  a  point 
too  low  for  the  proper  operation  of  the  coil.  The  second  point  to  investigate 
are  all  low  tension  wires  and  terminals.  The  terminals  may  have  worked  loose.. 
Again,  the  motor  may  have,  through  its  vibration,  caused  one  of  the  cables  to 
become  chafed  and  produced  a  short  circuit.  A  cable  may  even  be  broken 
within  the  insulation  and  not  be  revealed  in  a  casual  inspection.  An  interrup- 
tion to  the  battery  circuit  would  also  result  if  the  contact  points  failed  for  any 
reason  to  come  together.  This  fault  is  remedied  by  bringing  the  points 
together  as  described  in  the  previous  paragraph.  In  case  the  coil  does  fail 
to  vibrate,  there  is  no  reason  why  the  engine  may  not  be  operated  on  the 
magneto,  if  sufficient  cranking  speed  can  be  attained.  If  the  engine  does 
operate  on  the  magneto,  but  will  not  start  on  the  battery,  it  is  a  certain 
indication  that  the  current  from  the  battery,  wiring,  or  the  coil  is  at  fault. 
Should  the  battery  side  be  in  order  and  enable  the  engine  to  be  started,  but 
fail  to  operate  on  the  magneto,  the  difficulty  will  be  found  to  be  due  to  the 
magneto  interrupter  contacts  not  opening  sufficiently,  or  to  the  plugs  having 
too  great  a  gap. 

If  the  coil  vibrates  and  the  engine  fails  to  start,  the  next  point  to 
investigate  is  the  gas  supply.  If  the  carburetor  is  correct  and  the  engine  still 
fails  to  start,  the  wire  leading  from  the  coil  tCK  the  magneto  may  be  at  fault. 
Again,  the  fault  may  lie  with  the  magneto  points  failing  to  open.     If  the  trouble 


412 


Automotive  Trade  Training 


is  not  found  in  these  two  points,  inspect  the  magneto  grounding  terminal  for  a 
short  circuit.  Any  of  these  conditions  permits  of  the  battery  current  escaping 
to  ground  without  passing  through  the  magneto  primary  circuit.  If  no  current 
flows  here,  the  main  purpose  of  the  vibrating  duplex  system  has  failed  and  no 
high  tension  current  will  be  induced  within  the  magneto  secondary  circuit. 

JOB  143.     BOSCH  ADJUSTABLE  IMPULSE  STARTER  COUPLING. 

To  facilitate   the  starting  of  heavy  duty  motors   such  as  are   used  in  the 
larger  trucks  and  the  tractors,  the   Bosch  Adjustable   Impulse   Coupling  has 


Fig.  481.*    Type  CG-83  Coupling  Partly  Disassembled. 

been  developed.  The  usual  method  of  equipping  the  engine  with  some  auxiliary 
battery  ignition  system  for  starting  at  slow  cranking  speeds  is  thus  displaced. 
The  essential  feature  is  a  spring  device  which  is  so  fitted  to  the  magneto  that 
it  will  give  the  armature  a  short  quick  turn  when  the  engine  is  cranked  over  at 


Fig.  482. 


Magneto  Ignition  413 

slow  cranking  speeds.  The  device  is  so  designed  and  constructed  that  it  is 
automatically  disconnected  when  the  engine  attains  a  speed  of  from  160  to  180 
R.  P.  M. 

Construction  and  Design. — The  coupling  is  designed  in  three  main  parts, 
each  having  functions  to  perform  peculiar  to  it.  These  three  members  are: 
the  impulse  member,  the  driving  disk,  and  the  adjustable  drive  member. 

Impulse  Member. — As  noted  in  the  illustrations,  this  member  consists  of  a 
hardened  steel  housing,  which  is  mounted  directly  on  the  drive  shaft  of  the 
magneto.  Inside  of  the  housing  are  two  governing  or  arresting  weights  which 
may  move  in  and  out  guided  by  tongues  on  their  rear  which  fit  into  slots  in  the 
inner  face  of  the  housing.  When  the  coupling  is  turned  slowly,  the  tongues 
of  the  arrester  weights  alternately  engage  with  a  small  steel  block  that  is 
mounted  on  the  arrester  plate.  This  arrester  plate  is  mounted  on  a  fixed 
position  on  the  frame  of  the  magneto  and  does  not  revolve.  A  steel  spring  acts 
as  a  connector  between  the  housing  and  what  might  be  termed  its  cover  which 
is  known  as  the  driving  flange.  •  One  end  of  the  spring  is  held  in  the  outer  edge 
of  the  housing  while  the  other  is  held  in  the  hub  of  the  driving  flange.  The 
hub  of  the  driving  flange  carries  two  cams  which  lift  the  arrester  weights  at  the 
proper  instant,  thus  releasing  the  spring. 

Operation  of  Impulse  Member. — When  the  engine  is  cranked  the  impulse 
member  is  in  its  normal  position.  The  tongue  of  one  of  the  arrester  weights 
will  be  resting  against  the  arrester  block,  thus  holding  the  housing  stationary. 
As  the  engine  is  cranked  over,  the  driving  flange  revolves,  thus  winding  up  the 
spring  since  the  housing  is,  as  just  stated,  held  stationary.  At  a  fixed  point 
one  of  the  cams  of  the  driving  flange  lifts  the  arrester  weight  clear  of  the 
arrester  block,  the  wound  spring  thus  released.  The  impulse  coupling  housing 
which  is  mounted  on  the  armature  shaft  is  thus  given  a  quick  turn.  This 
causes  the  magneto  to  develop  and  deliver  an  intense  spark  to  the  cylinder  in 
firing  position.  With  the  engine  running,  the  centrifugal  force  developed  at 
160  to  180  R.  P.  M.  is  sufficient  to  throw  the  weights  in  the  coupler  housing  to 
its  outer  surface  where  they  are  held  by  the  same  force.  Above  these  speeds 
there  is  no  further  action  of  the  impulse  member  parts,  the  whole  unit  revolving 
and  transmitting  the  driving  effort  much  the  same  as  any  other  magneto 
coupling.     When   the   engine   has  been   stopped   the   weights  are   immediately 


41^  4i  40 


Pig.  483.    Adjustable  Driving  Member  Disassembled. 

returned  to  their  first  position.  The  student  should  understand  that  it  is  not 
the  speed  of  the  cranking  operation  which  governs  the  speed  of  the  magneto 
armature  action,  but  rather  the  strength  of  the  uncoiling  spring  which  controls 
the  armature  speed.  As  a  consequence  the  spark  delivered  by  the  magneto  is 
as  hot  or  intense  as  that  which  is  delivered  when  the  engine  is  operating  at  a 
speed  of  several  hundred  revolutions  per  minute.  There  is  no  danger  of  back- 
fire from  the  use  of  the  impulse  starter  coupling,  as  the  adjustment  is  such  that 
when  cranking  the  spark  occurs  always  after  the  piston  has  passed  T.  D.  C. 
The  Adjustable  Driving  Member. — This  member  is  made  of  hardened  steel 


414  Automotive  Trade  Training 

ihroughout.  The  outer  face  of  the  keyed  flange  carries  two  keys  which  fit  into 
slots  on  one  side  of  the  driving  disk.  The  inner  surface  is  knurled  as  is  the 
inner  surface  of  the  driving  hub  which  fits  into  and  against  it.  These  two  parts 
are  held  together  by  means  of  the  holding  plate  and  three  cap  screws.  This 
construction  permits  of  the  fractional  degree  adjustment  so  essential  to  exact 
magneto-to-engine  timing.  To  adjust  the  driving  member  the  cap  screws 
should  be  turned  part-way  out  until  the  hub  is  shown  to  be  loose  within  the 
driving  flange.  The  driving  flange  may  then  be  advanced  or  retarded  on  the 
hub  as  desired  and  the  whole  locked  together  as  one  unit  again  by  tightening 
the  three  cap  screws.     Be  certain  to  keep  the  lock  washers  in  place  on  these. 

Care  and  Maintenance. — In  case  it  should  be  necessary  to  disassemble  the 
coupling,  it  can  be  done  readily  if  some  care  is  used.  When  removing  the 
magneto  from  the  engine  the  adjustable  coupling  will  remain  on  the  engine 
while  the  driving  disk  will  be  loosened  and  laid  away.  The  driving  flange  may 
now  be  removed  from  the  housing  of  the  impulse  unit  by  pulling  it  away  from 
it.  Use  care  that  the  spring  does  not  fly  out.  Never  use  a  grease  to  lubricate 
the  impulse  unit.  Use  a  good  thin  oil  only  as  the  grease  will  harden  and 
interfere  with  the  free  action  of  the  weights. 

JOB  144.     EISEMANN  HIGH  TENSION  MAGNETO  G4. 

The  G4  type  of  Eisemann  magneto  may  be  considered  as  basically  repre- 
senting the  complete  line.  Certain  features  of  difference  will  be  noted  in  the 
description  of  the  other  types  under  their  respective  job  sheets. 

Generation  of  Current. — The  magnetic  field  is  created  and  maintained  by 
two  horse-shoe  magnets.  These  are  mounted  on  the  pole  shoes.  The 
armature  driven  at  engine  speed  is  mounted  between  the  pole  shoes.  Ball 
bearings  are  used  to  carry  it.  The  armature  is  of  the  H  or  double  T  type. 
It  has  a  combined  winding,  primary  and  secondary.  When  rotated  within 
the  field,  a  low  tension  current  is  induced  within  the  primary  winding.  When, 
at  the  moment  of  greatest  intensity,  this  circuit  is  broken  by  the  opening^  of 
the  contact  breaker  points,  this  break  causes  the  rapid  collapse  of  the  magnetic 
lines  of  force  about  the  core  of  the  armature.  This  in  turn  results  in  the 
induction  of  a  high  tension  current  within  the  secondary  winding  which  is  used 
to  jump  the  plug  gap  and  ignite  the  fuel  charge  within  the  cylinder.     One  end 


CDMENSER  ARMATURE         COLLECTOR  RING 

WINDING 

Fig.  484.    Eisemann  High  Tension  Armature,  H.  or  Shuttle  Type. 

of  the  secondary  winding  is  connected  to   the  collector  ring  from  which  the 
current  passes  to  the  distributor  and  thence  to  the  plugs. 

Armature. — The    armature    core    is    made    up    of   two    end   pieces    of   soft 
malleable   iron,   between   which   are   a   number   of   insulated   soft   sheet   steel 


Magneto  Ignition 


415 


laminations.  The  parts  are  riveted  together  in  such  manner  that  the  core  is 
one  solid  unit  in  appearance.  The  primary  winding  of  a  few  layers  of  medium- 
sized  copper  wire  has  one  end  grounded  to  the  armature  core,  thus  making 
connection  with  the  contact  breaker  mechanism  which  is  also  grounded.  Over 
this  primary  winding  are  wound  many  turns  of  very  fine  copper  wire.  The 
wire  used  is  insulated  and  these  several  layers  are  each  insulated  from  the  ones 
above  or  below  it.  The  beginning  of  the  secondary  is  connected  directly  to 
the  end  of  the  primary  winding,  while  the  end  of  the  secondary  is  led  to  the 
collector  ring  with  which  it  makes  electrical  contact.  This  arrangement 
grounds  the  secondary  winding  through  the  primary  winding  ground. 

Condenser. — The  condenser  which  is  built  in  at  one  end  of  the  armature, 
prevents  a  spark  occurring  at  the  opening  of  the  contact  breaker  points.  With- 
out the  condenser,  the  contact  points  would  be  burned  and  pitted  very  quickly. 
It  also  increases  the  intensity  of  the  spark  at  the  plugs.  The  illustration  of  the 
Eisemann  Armature  shows  the  method  of  mounting  and  protecting  the 
condenser.  This  illustration  also  shows  the  windings,  the  collector  rings,  the 
bearings,  and  the  gear  driving  the  distributor  gear. 

Contact   Breaker. — This  part  is   so-called  because   the   separation   of   the 


DISTRIBUTOR    PLATE 

WITH 

WATER-PROOF  CABLE   FASTENINGS 


INDICATOR  POINT 

FOR    SETTING   MAGNETO* 

TO   MOTOR 


DISTRIBUTOR 

ROTATING 

DISC. 


SETTlNcr 
MARKS 


DISTRIBUTOR 
CARBON   BRUSHES 


CARBON  BRUSH 

TO  PICK  UP 
CURRENT  FROM 
COLLECTOR.RING 


CABLE  CONNECTION 
FOR  CUTTING  OFF 
MAGNETO. IGNITION 


WATER.PROOF  END 
CAP  FOR    BREAKER 


TIMING  LEVER  BODY 

Fie:.  485.    Disassembled  view  of  Eisemann  G4  Magneto 


MAGNETO  CONTACT 
BREAKER  POINTS 


416 


Automotive  Trade  Training 


platinum  contacts  breaks  or  interrupts  the  primary  circuit.  The  contact 
breaker  is  shown  in  Fig.  485.  A  brass  disk  fastened  in  the  end  of  the  armature 
carries  the  mechanical  and  electrical  elements  of  the  breaker  on  its  face. 
Mounted  on  this  face  is  a  stationary  insulated  contact  block.  The  contact 
block  carries  the  fixed  contact  point.  Electrical  connection  is  made  from  the 
block  to  the  primary  winding  end  by  means  of  the  screw  holding  the  entire 
breaker  in  place.  Operating  against  this  fixed  contact  is  another  platinum 
contact  mounted  on  a  bell  crank  lever  or  rocker  arm.  This  lever  is  operated 
by  riding  over  two  flat  steel  cams  mounted  in  the  timing  lever  body.  The 
contacts  are  normally  held  in  a  closed  position  by  a  fiat  steel  spring.  The 
.moving  contact  is  also  grounded  through  this  spring.  To  maintain  the  breaker 
mechanism  in  proper  time  with  the  engine  and  armature  position  it  is  set  by  a 
key  formed  on  its  conical  part.  The  key  is  fitted  into  a  key  way  in  the 
armature.  If  for  any  reason  the  breaker  is  removed  the  key  and  key  way  must 
be  carefully  fitted  together  when  it  is  replaced. 

Distributor. — A  brush  in  the  distributor  plate  receives  the  high  tension 
current  from  the  collector  ring.  Refer  to  Fig.  485.  This  center  brush  makes 
contact  with  the  T  shaped  metal  insert  of  the  distributor  disk.  The  disk  is 
attached  to  the  distributor  gear  and  rotates  with  it.  As  it  rotates  the  metal 
insert  makes  contact  in  turn  with  each  of  the  carbon  brushes  on  the  distributor 
plate  which  are  in  connection  with  the  spark  plug  wires. 

The  proper  fastening  of  the  cables  to  the  distributor  plate  is  important. 
If  not  properly  installed  water  may  short  circuit  them.  All  connections  are  on 
the  inside  where  they  are  protected.  The  high  tension  cables  are  fastened  by 
winding  the  end  of  the  wire  about  the  carbon  brush  holder,  and  clamping  it  in 
position  with  the  hexagon  nut. 

Housing. — The  housing  is  of  unit  cast  construction.  The  iron  pole  shoe  is 
cast  in  non-magnetic  metal.  ^  This  makes  a  compact  and  rigid  housing  for  the 
vital  elements  where  they  are  certain  to  be  maintained,  free  of  water,  dirt,  oil, 

and  other  foreign  elements,  in  their 
proper  position.  Since  the  hq^using 
can  be  machined  as  one  piece, 
closer  fits  between  the  armature 
and  pole  shoes  are  possible.  This 
tends  to  give  better  operating  con- 
ditions for  the  magneto  and  a 
hotter  spark. 

Spark  Control. — As  the  spark 
occurs  only  when  the  primary  cir- 
cuit is  broken  by  the  opening  of 
the  contacts,  the  timing  of  the 
spark  can  be  controlled  by  having 
these  contacts  open  sooner  or  later 
with  reference  to  the  fly  wheel 
travel  or  top  dead  center  position 
of  the  pistons.  The  timing  range 
is  30  degrees  accomplished  by  the 
angular  movements  of  the  timing 
lever  body.  The  spark  is  retarded 
~  when  the  movement  is  in  the  direc- 

Fig.  486.    Unit  Cast  Housing.  ^.^^     ^^     rotation,     and     advanced 

when  the  timing  lever  is  pushed  in  the  direction  opposite  to  the  direction  of 
rotation.  In  fixed  ignition  the  timing  lever  body  is  not  equipped  with  con- 
trolling arms.  In  this  case  it  is  set  at  the  point  of  greatest  spark  intensity 
and  any  advance  or  retard  must  be  of  a  permanent  nature.     By  this  is  meant 


Magneto  Ignition 


417 


that  the  spark  is  set  to  occur  at  a  fixed  position  of  the  piston  travel,  whether 
the  engine  speed  be  fast  or  slow.  The  only  change  of  setting  possible  with 
relation  to  the  engine  is  by  making  a  change  of  the  timing  with  the  engine. 
This  must  be  done  with  the  coupling,  if  that  is  adjustable,  or  with  the  magneto 
shaft  timing  gear  drive  on  the  engine  by  advancing  or  retarding  the  gear  a 
tooth  or  so. 

Timing  the  Magneto  to  the  Motor. — First  remove  the  distributor  plate 
having  the  magneto  bolted  in  position  with  the  coupling  free.  Next  bring  the 
setting  mark  on  the  distributor  disk  to  the  indicator  point  by  rotating  the 
armature  by  hand.  For  magneto  rotating  clockwise  use  setting  mark  R.  For 
magneto  rotating  anti-clockwise  use  the  setting  mark  L.  With  the  armature 
in  this  position  the  points  are  just  separating,  and  the  metal  insert  is  in  contact 
with  the  carbon  brush  for  cylinder  No.  1.  Next,  bring  the  piston  in  cylinder 
No.  1  to  top  dead  center,  compression  stroke.  The  magneto  and  the  engine 
drive  shaft  may  now  be  connected  using  some  form  of  flexible  coupling.  Use 
extreme  care  to  maintain  the  magneto  and  engine  in  proper  position  until  this 
work  is  accomplished. 

Safety  Spark  Gap. — Should  the  spark  cable  become  disconnected  or  broken, 
or  should  the  plug  gap  be  too  wide,  the  high  tension  current  in  attempting  to 
find  a  ground  may  puncture  the  insulation  of  the  armature  or  other  parts. 
The  safety  gap  consists  of  a  pointed  screw  placed  in  the  housing  at  a  certain 
distance  from  the  collector  ring.  The  high  tension  current,  failing  to  find  its 
usual  path  to  the  plugs  available,  will  pass  from  the  collector  ring  to  this 
screw  and  is  thus  grounded. 

JOB  145.     EISEMANN  MAGNETO  GA  4. 

Automatic  Spark  Advance. — This  magneto  is  the  same  general  type  as  the 
standard  G4  with  the  addition  of  the  automatic  spark  advance.  The  automatic 
spark  advance  is  accomplished  by  the  action  of  centrifugal  force  on  a  pair  of 
weights  at  one  end  linked  to  a  sliding  block.     This  block  is  fitted  over  the 


Fig.   487.     Eisemann   Automatic   Spark  Advance. 

spindle  of  the  magneto.  The  other  end  of  the  weights  is  hinged  to  the 
armature  structure.  Along  the  armature  spindle  run  two  helicoidal  splines 
which  engage  in  similarly  shaped  grooves  in  the  sliding  block.  A  coil  spring 
pressing  against  this  block  keeps  the  governor  normally  closed,  when  the 
motor  is  running  slowly.     In  this  position  the  spark  is  fully  retarded. 


418 


Automotive  Trade  Training 


As  the  engine  speeds  up,  the  centrifugal  force  causes  the  governor  weights 
to  spread  out,  drawing  the  sliding  block  lengthwise  against  the  spring  and 
compelling  the  helicoidal  splines  to  cause  angular  displacement  of  the  block. 
This  action  advances  the  armature  relative  to  its  former  position  on  the  shaft 
and  as  a  result  of  this  movement  the  armature  is  advanced  in  its  relation  to 
piston  travel.  The  faster  the  engine  travels  the  greater  the  centrifugal  force 
and  the  greater  the  distance  the  block  travels.  The  advancing  and  returning 
of  the  block  on  its  path  regulates  the  advance  and  retard  of  the  spark.  The 
spring  acts  against  the  centrifugal  force  in  controlling  the  weights  and  is 
responsible  for  the  retarding  of  the  spark.  The  action  of  the  governor  is 
steady  at  all  points  and  speeds. 

With  this  method  of  advance  the  moment  of  induction  is  brought  about 
earlier  by  moving  the  entire  armature  and  with  it  the  breaker.  The  cams 
causing  the  break  are  fixed  in  the  correct  position  to  cause  the  break  to  occur 
at  the  moment  when  the  current  in  the  winding  is  the  strongest.  As  a  con- 
sequence of  this  action  the  spark,  whether  at  advance  or  retard,  is  always  at 
its  maximum  intensity.     This  is  a  distinct  advantage. 


DISTRIBUTOR    PLATE 

KITH 

f  JITER-PROOF  CABLE   FASTENINOS 


INDICATOR  POINT 

FOR   SETTING   MAGNETO 

TO  MOTOR 


DISTRIBUTOR 

ROTATINa 

DISC 


SETTINO 
MARKS 


DISTRIBUTOR 
CARBON    BRUSHES 


CARBON  BRUSH 
PICK  UP  CURRENT 
FROM  COLLECTOR  RING 

CABLE  CONNECTION, 
FOR  CUTTING  OFF  MAGNETO 
IGNITION 


WATERPROOF  END 
CAP  FOR   BREAKERS 


BINDING  POST 

FOR  BATTERY 

BREAKER 


TIATER.PROOF  NUT 
FOR  BATTERY 
BINDING  POST 


TIMING  LEVER  BODY 


MAGNETO  CONTACT 
BREAKER  POINTS 


Fig.  488.    Disassembled  view  of  Eisemann  Type  GR4,   II  Edition. 


Magneto  Ignition 


419 


JOB  146.     EISEMANN  DUAL  IGNITION. 

Magneto. — The  Type  GR4,  II  Edition,  is  described  and  illustrated  here. 
In  the  main  this  magneto  is  the  same  as  the  independent  type.  It  differs  in 
two  important  points.  An  additional  breaker  for  use  in  connection  with  the 
battery  circuit  is  supplied.  The  distributor  is  so  modified  as  to  permit  of  its' 
electrical  separation  from  the  magneto  armature  when  distributing  the  battery- 


Fig.  489.     Eisemann  Dual  Ignition  Coll. 

spark.  The  distributor  and  breaker  construction  is  shown  in  Fig.  488.  The 
general  care  of  the  GR4  is  the  same  as  for  the  G4  described  in  Job  144.  The 
magneto  may  be  used  in  connection  with  either  of  the  dash  coils  illustrated. 

Coils. — The   DC  and   the   DCR  coils   differ  only   in   the   arrangement  for 
starting  on  the  spark  or  push  button  starting.     The  DC  coil  has  a  push  button 


420 


Automotive  Trade  Training 


arrangement  giving  a  single  spark  for  starting  when  the  crank  shaft  and 
pistons  have  stopped  in  such  a  positic-i  that  the  breaker  points  for  the  battery- 
current  are  open.     The   DCR  has  a  mechanical  ratchet   device,   illustrated  in 


Magneto  Ignition 


421 


Fig.  489,  which  will  give  a  shower  of  sparks  in  the  cylinder  no  matter  what 
the  position  of  the  pistons.  Rapid  twisting  back  and  forth  of  the  starting 
handle  on  the  front  of  the  coil,  causes  the  toothed  ratchet  in  the  center  by 
acting  against  the  fiber  roller  A  to  oscillate  the  lever  B,  which  in  turn  makes 
contact  alternately  at  C  and  D,  thus  giving  a  rapid  sequence  of  sparks  at  the 
plug  then  in  contact  with  the  distributor  brush  through  its  usual  circuit. 

Wiring. — Fig.  490  gives  the  full  wiring  diagram  for  the  Eisemann  Dual 
System.  The  student  can  trace  out  the  various  circuits,  and  by  referring  to  the 
parts  shown  in  Fig.  488,  can  readily  trace  out  the  internal  circuits.  It  has 
been  found  advisable  to  time  the  battery  spark  about  ten  degrees  later  than 
the  magneto  spark  as  a  permanent  timing  difference.  This  is  an  added 
advantage  in  starting  with  the  hand  crank  as  the  danger  from  a  back  fire  is 
materially  lessened. 

A//  c<?d/es  shou/d  be  pushed  in  as  far  as poss/6/e.  // /sty/so 
very  ad^/sa6/e  fo  conso/idafe  the sfranded ends  tyjth  s o/der. 

Low   Tension    Cable 
(Strfp  for  %y. 


\'Hi^h  Tension  Co6/^ 
(Strip  for  y^eh 

Ti<jhfen  bind  mo 
screws    firm/y.^ 


__Sfirlng  for  carbon 
brush  can  be  re— 
p/aced  more  eas- 
^      **"    1  1/y  /f  the  brush  be 

^^^^^^•^.-ii^-**^       revo/\/ed  between 
the  fingers  vyhi/e 
SAiD  CAP,  ^  .^ling  inserted. 


P/STRiBUTOR  PLATS 


Pig.  491.     Connecting  Cables  to   Distributor  Plate. 

The  attaching  of  the  cables  to  the  spark  plugs  must  be  made  in  accordance 
with  the  firing  order  of  the  motor.  The  proper  fastening  of  the  cables  to  the 
distributor  and  the  end  cap  is  of  very  great  importance  in  order  to  prevent 
water  or  any  other  electrical  conductor  making  avshort  circuit  between  the 
different  connections.  Fig.  491  illustrates  how  ^ese  cables  should  be  attached. 
The  connection  screw  with  the  round  head  must  not  be  used  for  the  end  cap 
as  the  round  head  will  not  clear  the  breaker  mechanism.  The.^ti5"und  head 
screw  belongs  in  the  distributor  and  should  be  kept  there.      ■^'    *  ' x 

The  dual  system  will  operate  on  either  dry  cells  or  storage  b^ery.  The 
latter  is  recommended  by  the  manufacturers  and  a  six-volt  size  shoOTd  be  used. 

Dual  System  Troubles. — If  the  ignition  is  suspected  in  case  of  the  motor 
failing  to  start,  the  first  step  in  locating  the  trouble  is  to  find  whether  the 
trouble  is  in  the  plugs,  coil,  or  magneto,  or  any  oi  their  respective  circuits. 
The  plugs  are  the  most  frequent  source  of  trouble  and  should  be  examined 


422 


Automotive  Trade  Training 


first.     See    that   the   plug   gaps    are    all    equal    and    from    1/64"    to    3^2"    apart. 
Inspect  also  for  fouled,  broken,  or  cracked  porcelains. 

Contact  Points. — Clean  these  with  gasoline  until  they  appear  quite  white. 
If  pitted,  or  burned,  a  platinum  point  file  should  be  used  to  carefully  true 
them  up.  Set  the  point  gap  to  as  near  .012"  as  is  practicable.  As  these  points 
wear  away  in  time,  they  should  be  adjusted  by  giving  the  regulating  screw  a 
forward  turn.  First  release  the  locking  nut,  and  after  the  points  are  set  the 
lock  nut  must  be  secured  in  position  again.  If  an  Eisemann  wrench  is  at  hand, 
use  the  gauge  on  its  handle  to  test;  otherwise  use  the  feeler  gauge  to  secure 
the  .012"  distance.  The  eye  cannot  be  trusted  to  estimate  this  distance.  If  all 
of  the  platinum  is  worn  off  the  contacts,  new  ones  will  have  to  be  inserted. 
In  this  case  the  contacts  are  removed  until  the  new  ones  are  in  their  places 
when  the  final  adjustment  is  made  with  the  breaker  in  position  on  the  magneto. 


For  4  Cylinder  Engines. 


For  8  Cylinder  Engines. 


For  12  Cylinder  Engines. 


Fig.  492. 


Impulse  Starter  Coupling. 
Splitdorf  Dixie  Magnetos. 


Magneto  Ignition 


423 


Testing  the  Magneto.^If  the  motor  refuses  to  start  or  run  on  magneto 
after  the  points  are  correct,  and  the  plugs  and  cables  are  found  correct, 
the  magneto  should  be  tested  to  see  if  it  is  generating  a  spark.  First  remove 
the  distributor  plate.  Next,  rest  the  blade  of  a  screw  driver  on  the  gear 
housing  having  same  in  metallic  contact.  Bring  the  point  of  the  blade  close 
to  the  collector  ring,  about  %".  Crank  the  motor.  If  a  spark  jumps  from  the 
ring  to  the  blade  the  magneto  is  generating  and  the  fault  is  not  within  it, 
unless  it  should  be  in  the  brushes  or  distributor.  If  these  parts  on  examination 
are  found  to  be  correct,  the  trouble  is  elsewhere,  possibly  in  the  coil,  battery, 
or  even  in  some  other  system  than  the  ignition  system.  The  gasoline  system 
will  frequently  develop  faults  which  are  hard  to  tell  from  ignition  faults. 

Operating  Engine  Without  Coil. — To  test  the  coil  and  magneto  in  case  of 
trouble,  the  student  will  want  to  remember  that  it  is  possible  to  operate  the 
engine  on  the  dual  magneto  using  it  as  an  independent  source  of  ignition.  To 
do  this,  first  disconnect  all  wires  leading  from  the  magneto  to  the  coil.  Next, 
connect  the  cables  marked  H  and  HM  on  the  distributor  plate  thus  making  a 
direct  path  from  the  collector  ring  to  the  distributor  plate.  The  instrument 
then  may  be  used  as  an  independent  magneto.  To  stop  the  engine  a  wire  is 
led  from  the  MA  connection  on  the  end  cap  to  the  dash,  and  grounded,  which 
acts  as  a  simple  switch. 

JOB  147.     DIXIE  MAGNETO.     AERO  MODELS  448-449  AND  648-649. 

Principle  of  Operation. — The  Dixie  Magneto  made  by  the  Splitdorf 
Electrical  Co.  is  of  the  inductor  type  having  the  coil  windings  mounted  on  the 
pole  shoes  above  the  inductor  or  rotating  element.  As  will  be  noted  in  the 
illustrations  the  mounting  of  the  magnets  is  quite  different  from  that  of  most 
high  tension  instruments. 


Fig.  493.     Rotating  Element  of  the  Magneto. 

Unidirectional  Sparks. — The  student  will  remember  that  at  the  beginning  of 
this  chapter  the  direction  of  the  passage  of  the  high  tension  spark  was  discussed. 
From  the  usual  H,  or  armature  type  of  machine,  the  design  is  such  that  one-half 
of  the  sparks  go  to  the  plugs  through  the  ground,  and  return  to  the  instrument 
through  the  cables,  while  the  other  half  go  through  the  cables  to  the  center 
electrode  of  the  plug,  and  return  to  the  magneto  through  the  engine  frame. 
The  Dixie  is  so  arranged  as  to  have  all  of  the  sparks  travel  in  one  direction. 


Fig  iMA. 


Magnetic  Flux.  — 


Fig.  494B. 


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Automotive  Trade  Training 


Rotating  Element. — The  rotating  element,  or  inductor,  is  made  up  of  a 
shaft  and  core  having  four  wings  or  poles  cast  integral.  This  is  shown  in  Fig, 
493. 

Magnetic  Flux. — In  Fig,  494A  the  magnetic  flux  flows  in  one  direction 
through  core  5.  When  wing  N  is  opposite  3,  flux  flows  to  3  and  through  5  to  4, 
back  to  wing  S  of  opposite  polarity.  Until  the  wing  N  has  passed  the  leaving 
pole  piece  3,  the  action  of  the  cam  holds  the  breaker  contacts  apart,  thereby- 
preventing  the  induction  of  current  within  the  primary  circuit  about  the  core 
5.  This  leaves  the  core  free  from  magnetic  interference  and  prepares  it  for  a 
powerful  magnetic  and  electrical  action  when  the  polarity  of  the  field  structure 
and  core  is  reversed  upon  further  rotation  of  the  rotor. 

Fig,  494B  shows  the  magnetic  flux  flowing  in  the  reverse  direction  through 
core  5,  Wing  N  has  moved  over  to  4  and  the  directon  of  flow  of  flux  has 
been  reversed  now  flowing  from  4  through  5  to  3.  When  wing  S  passes  the 
leaving  pole,  piece  3,  the  action  of  the  cam  separates  the  platinum  contact  of 
the  breaker  thus  interrupting  the  primary  current  which  has  been  built  up  in 
the  primary  winding  of  the  core  5.  The  induction  of  the  secondary  current 
occurs  in  the  secondary  winding  of  the  core  5  as  the  points  separate,  breaking 
the  primary  current  and  causing  the  collapse  of  the  lines  of  force  about  the 
core.  The  reversal  of  polarity  of  the  core  assures  its  complete  demagnetiza- 
tion, and  the  consequent  lively  action  of  the  instrument  in  producing  the  high 
tension  spark. 

Magneto  Czire. — The  proper  space  between  the  interrupter  points  is  .020". 
Be  certain  the  gauge  used  is  the  proper  size.  The  platinum  points  should  be 
kept  free  of  all  dirt,  dust  and  oil.     Should  they  become  burned  or  pitted  from 

constant  service,  the  platinum  point 
file  may  be  used  to  true  them  up.  The 
utmost  care  must  be  used  to  have  them 
making  contact  over  the  entire  surface. 
The  distributor  block  should  be  re- 
moved occasionally  and  inspected^  for 
an  accumulation  of  carbon  dust.  Clean 
with  a  cloth  moistened  with  gasoline. 
Dry  with  a  clean,  dry  cloth. 

Do  not  pull  out  on  the  carbon 
brush  to  increase  the  tension  on  the 
spring. 

Oiling.— Refer     to     Fig.     495.     For 
passenger  cars  the  magneto  should  be 
oiled    at    A    with    four    drops    of    very 
Fig.  495.    Points  tor   Oiling,  light  oil  every  1000  miles  of  operation; 

at  B  with  2  drops  every  1000  miles,  and 
at  C  one  drop  of  light  oil  should  be 
applied  to  the  bearing  of  the 
breaker  bar  with  a  tooth  pick  every 
200  hours  of  operation.  Fig.  496 
illustrates  the  breaker  base  and  the 
hole  for  oiling  the  breaker  bar 
bearing.  Every  possible  precaution 
should  be  taken  to  prevent  the  oil 
from  getting  on  the  platinum 
points.  The  magneto  will  not  ope- 
rate satisfactorily  if  this  happens. 
Flashing  at  the  points  and  misfir- 
ing of  the  engine  will  be  evident.  Fig.  496.    Oiling  Diagram. 


Magneto  Ignition 


425 


When  the  Dixie  is  used  as  the  ignition  source  on  trucks  and  tractors  the 
points  A  and  B  will  require  oiling  at  more  frequent  intervals.  Point  C  the 
same. 

Timing  the  Magneto  to  the  Engine. — First  bring  piston  No.  1  to  the 
top  of  the  compression  stroke.  Next,  retard  the  spark  timing  lever  fully. 
While  rotating  the  magneto  in  the  direction  it  is  driven,  the  breaker 
points  should  be  observed.  Continue  turning  the  rotor  armature  until  the 
points  are  just  about  separating.  Maintaining  the  magneto  in  this  position,  the 
coupling  to  the  engine  may  be  effected.  Next  secure  the  instrument  to  the 
engine. 

Without  changing  the  position  of  -the  parts,  the  distributor  cover  is 
removed  to  determine  which  terminal  of  the  distributor  block  is  in  contact 
with  the  finger  of  the  disk.  Lead  the  plug  wire  from  this  terminal  to  cylinder  No. 
1.  Connect  the  remaining  plug  wires  in  turn  according  to  the  proper  sequence 
of  firing  of  the  cylinders. 

JOB  148.     DIXIE  MAGNETO.     MODELS  46,  462  AND  246. 

The  Dixie  Magneto  is  of  the  high  tension  inductor  type.  The  rotating 
member  or  inductor  consists  of  two  pieces  of  magnetic  material  separated  by 
a  non-magnetic  centerpiece.     Since  the  magnets  are  mounted  just  outside  the 


Fig.    497.    Magneto    with    Cover    and    One   Magnet    Withdrawn. 

magnetic  parts  of  the  rotor,  these  are  really  rotating  pole  pieces.  The  polarity 
of  the  pole  pieces  does  not  change  as  the  rotor  is  turning.  Change  of  polarity 
takes  place  only  in  the  laminated  field  pieces  and  core  of  the  winding.  There 
is  no  winding  on  any  of  the  rotating  parts.     A  core  carrying  both  primary  and 


Fig.  498.    Rotating  Poles,  Bearing  Holders  and  Field  Structure. 


426 


Automotive  Trade  Training 


high  tension  winding  is  housed  under  the  arch  of  the  magnets  above  the  rotor. 
The  core  of  this  winding  is  fastened  to  the  field  pieces.  The  field  pieces  and 
winding  are  mounted  together  and  made  to  turn  back  and  forth  to  give  the 
advance  and  retard  of  the  spark.  The  breaker  is  stationary.  No  sliprings  or 
brushes  are  necessary  since  there  are  no  rotating  windings. 

The  winding  and  the  condenser  can  be  removed  from  the  magneto  without 
removing  the  instrument  from  the  engine.  The  condenser  is  readily  accessible 
and  placed  in  a  position  where  it  is  connected  directly  across  the  primary 
winding  breaker  points. 


Fig.  499.    Dixie  Magneto 
Switch. 

Magneto  Care. — The  directions  given  in  Job  147  apply  to  these  models  as 
well. 

Dixie  Magneto  Switch. — The  Dixie  Magneto  breaker  cover  is  provided 
with  a  terminal  for  connecting  the  primary  to  the^rounding  switch.  The  wire 
leading  to  the  switch  from  the  magneto  must  be-.^ttached  to  the  insulated 
terminal.  The  other  terminal  is  grounded  by  running  a  wire  from  it  to  the 
car  frame. 

JOB  149.     THE  SPLITDORF  IMPULSE  STARTER. 

The  action  of  the  impulse  starter  may  be  compared  to  a  cranking  speed 
of    about    500    R.    P.    M.     This    is    possible    since    the    impulse    starter    is    so 

constructed  that  at  very  slow  cranking  speeds  the 
armature  is  caught  and  held,  until  at  the  proper 
point  on  the  compression  stroke  the  spring,  which 
has  been  put  under  tension,  is  released,  and  the 
armature  snapped  forward  at  a  high  rotative  speed, 
until  it  again  resumes  its  natural  position  with 
reference  to  the  engine.  The  action  is  as  follows: 
Referring  to  Fig.  501.  The  member  A  is 
keyed  to  the  drive  shaft  of  the  magneto  and  con- 
tains the  notches  C  and  D.  The  pawl  E  carries 
projections  F  and  G,  and  is  movable  about  its  axis 
H.  The  cam  member  J  has  two  cams  K  and  L 
and  also  carries  the  trip  lever  M. 

When  starting  the  engine,  the  parts  rotate  at 
low  speed  and  the  centrifugal  force  is  not  sufficient 
to    throw   the    trip    lever    M    out   from    the    center, 
hence   the  point   N  of  the  lever  engages  with   the 
Fig.  500.     Cover  Removed  to  projection   G  of  the  pawl  and  causes  projection  F 
Show    Impulse    Starter.        f  •^t.a.i.^i-        r-  t\ 

to  engage  with  the  notches  C  or  D. 

The  member  A  is  now  prevented  from  turning,  but  cam  member  J  con- 
tinues to  turn  and  compresses  the  coil  spring  U  insitle  of  A  until  cam  K  or  L 


Magneto  Ignition 


427 


releases  the  projection  F.  The  coil  spring  then  rotates  the  member  A  at  high 
speed,  and  as  it  is  keyed  to  the  magneto  shaft  a  strong  spark  is  produced  at 
the  plug.  This  spark  always  occurs  several  degrees  past  top  dead  center, 
regardless  of  the  position  of  the  spark  lever,  advanced  or  retarded. 


Fig.   501.     Details  of  Construction   and   Operation  of  Impulse  Starter. 

The  pawl  projection  F  continues  to  engage  in  notches  C  or  D  until  the 
speed  reaches  150  to  200  R.  P.  M.,  at  which  the  blow  from  the  cam  is  sufficient 
to  throw  the  pawl  E  against  the  stop  X  into  an  inoperative  position. 

At  this  speed  the  trip  lever  M  is  thrown  out  by  centrifugal  force  so  that  it 
no  longer  engages  with  pawl  projection  G  as  the  trip  lever  does  not  engage 
above  120  R.  P.  M.  This  permits  of  the  engine  being  throttled  down  to  idling 
speed  without  the  trip  lever  coming  into  action. 

The  lever  P  on  the  side  of  the  housing  is  provided  in  order  that  the  pawl  E 
can  be  engaged  by  hand  if  necessary.  The  cover  plate  is  provided  with  a  large 
felt  gasket  to  exclude  dust  and  other  foreign  substances.  See  that  this  is 
always  maintained  in  good  condition. 

The  stop  X  is  adjustable.  Moving  it  to  the  right  permits  the  starter 
mechanism  to  come  in  or  function  at  lower  speeds. 

Impulse  Starter  Care. — The  spring  is  packed  in  grease.  If  it  is  necessary 
at  any  time  to  renew  the  supply,  use  a  grade  which  will  not  harden  in  cold 
weather.  The  starter  mechanism  may  be  cleaned  by  removing  one  of  the 
screw  plugs  and  injecting  kerosene  with  an  oil  gun. 

To  replace  the  spring  first  insert  a  nail  or  pin  through  the  lateral  hole,  as 


Sci 


Fig.   502.    Method   of   applying   Impulse   Starter   Spring. 


428 


Automotive  Trade  Training 


shown  in  the  illustration.  Next  press  the  ends  of  the  spring  into  the  recess. 
The  middle  section  of  the  spring  may  then  be  forced  to  its  position  within  the 
recess.  This  method  of  assembling  leaves  a  suitable  space  between  the  two 
spring  ends  for  assembling  the  cam  member  J,  with  its  top  member  in  this 
space,  after  which  the  pin  or  nail  is  removed. 

The  member  A  may  be  removed  from  the  magneto  shaft  by  inserting  a 
screw  driver  or  similar  tool  into  the  opening  at  each  side  of  the  housing. 
These  openings  are  normally  closed  by  the  buttons  R  and  S  and  held  in  place 
by  the  buttons  Q. 

The  impulse  starter  should  never  be  thrown  into  engagement  while  the 
engine  is  running.  To  do  so  is  likely  to  result  in  damaged  parts  of  the 
mechanism. 

JOB  149A.     SPLITDORF  ADJUSTABLE  MAGNETO  COUPLING. 

This  coupling  is  designed  to  give  any  degree  of  magneto-to-engine  timing 
that  is  desired.  Figs.  503  and  504  show  the  coupling  in  detail  and  in  assembled 
section. 

When  the  cone  is  drawn  into  the  collar  by  rneans  of  the  large  nut  on  its 


Fig.  503.    Details  of  Splitdorf  Adjustable  Magneto   Coupling. 

threaded  outside,  the  cone  clamps  onto  the  shaft,  the  collar  setting  tightly  on 
the  cone,  making  a  compact  whole  which,  through  a  tongue,  drives  the  floating 
member. 

By  loosening  the  nut  and  the  collar  on  the  cone  the  collar  is  made  free 


Fig.   Sk.    Cross    Section   of    Splitdorf   Adjustable  Magneto   Coupling. 

to  turn.  Since  it  alone  carries  the  driving  tongue  the  relation  of  the  magneto 
time  to  the  drive  shaft  is  easily  attained.  When  the  desired  timing  position  is 
attained,  the  collar  is  locked  onto  the  cone.  Be  certain  to  have  the  lock 
washer  in  position  under  the  locking  nut. 


CHAPTER  14 

STARTING  MOTORS  AND  GENERATORS 

In  Chapter  11  dealing  with  the  fundamentals  of  electricity  and 
magnetism,  the  general  characteristics  of  motors  and  generators  were 
discussed.  There  are  two  distinct  types  of  equipment  in  popular 
favor.  In  one  case  the  starting  motor  and  generator  are  combined 
in  one  instrument  giving  the  Single  Unit  System.  In  the  other  case 
the  starting  motor  is  built  separate  and  apart  from  the  instrument 
used  for  generating  current  and  this  method  of  construction  and 
design  is  known  as  the  Two  Unit  System.  In  actual  service  there 
seems   to   be   little   choice   between   the   two   types.     Most   excellent 


Fig.  505.     Buick  Delco  Motor  Generator. 


instruments   of   each   type   are   manufactured   by  a   number   of   com- 
panies. 

Division  of  Duties. — Whether  the  type  be  the  single  or  double 
unit,  the  division  of  duties  of  the  instruments  is  the  same.  The 
storage  battery  is  common  to  each  instrument.  In  the  work  of 
cranking  the  motor,  the  battery  furnishes  a  heavy  surge  of  current 
(150  to  300  amperes)  to  do  the  work  of  turning  the  armature  over 
as  it  in  turn  turns  over  the  engine  through  the  medium  of  gears  or 
chains.     The  parts  in  circuit  when  the  engine  is  being  cranked  are 

429 


430 


Automotive  Trade  Training 


the   battery,   the   starting   switch,   the   brushes   and   starting   motor 
armature,  and  field  windings. 

Once  the  engine  has  started  to  operate  on  its  own  power,  the 
operator  opens  the  starting  switch  thus  opening  the  starting  circuit, 
and  stopping  the  drain  on  the  battery.    As  the  engine  speed  increases. 


Fig.  506.     Pierce  Arrow  Generator  with   Voltaj^e    Ket?ulator. 

the  generator  being  driven  by  the  engine  is  brought  to  a  point  at  which 
the  voltage  within  the  internal  circuit  of  the  generator  is  higher 
than  the  E.  M.  F.  (Electro  Motive  Force)  of  the  battery.  At  this 
point  the  battery  to  generator  circuit  is  closed  and  current  starts  flow- 
ing to  the  battery  from  the  generator.  In  this  way  the  current  drawn 
from  the  battery  for  cranking  the  engine  as  well  as  that  used  for 
lighting  and  ignition  is  replaced.  The  generating  circuit  includes  the 
generator,  the  battery,  the  ammeter,  and  the  cut-out  relay,  as  well 
as  the  fuses  in  some  cases.  The  cut-out  relay  or  automatic  cut-out 
serves  the  purpose  of  cutting  the  battery  into  and  out  of  circuit  with 
the  generator  in  an  automatic  manner.  This  prevents  the  battery 
discharging  through  the  generator  when  the  generator  is  operated  at 
speeds  too  low  to  overcome  the  battery  voltage.  This  is  explained 
more  fully  at  a  later  point. 

The  division  of  duties  as  outlined  for  the  generator  and  starting 
motor  applies  equally  whether  the  system  is  the  single  or  the  two 
unit  system.  In  a  general  way  also  the  method  of  control  of  the  gen- 
erator output  applies  to  either  type. 

Regulating  Generator  Output. — Owing  to  the  fact  that  there  are 
unusual  conditions  and  obstacles  confronting  the  engineers  designing 
generators  for  automotive  equipment,  it  is  perhaps  well  for  the 
student  and  mechanic  to  have  an  understanding  of  these  conditions. 


Starting  Motors  and  Generators 


431 


The  speed  of  the  engine  is  variable.  The  speed  of  the  generator, 
depending  as  it  does  on  the  engine  speed,  is  also  variable.  The 
generation  of  the  current  within  the  dynamo,  which  is  what  the  in- 
strument in  reality  is,  is  always  dependent  on  the  following  factors, 
three  in  number. 


Fig.  507.     Westinghouse  Starting  Motor. 

The  first  of  these  is  the  magnetic  field  or  magnetic  flux. 

The  second  is  the  conductors  which  are  made  to  cut  this  mag- 
netic flux. 

The  third  is  the  power  causing  the  conductors  to  rotate  in  the 
field  and  cut  the  flux,  in  this  case  the  engine. 

In  order  to  have  the  instrument  generate  electrical  current,  all 
three  of  these  factors  must  be  available  and  working  together  in 
proper  relationship.  The  voltage  which  is  then  generated  is  always 
proportional  to  the  product  of  these  three  factors.  That  is,  the 
strength  of  the  magnetic  field  with  the  number  of  armature  con- 
ductors, with  the  speed  of  armature  rotation,  governs  the  voltage 
or  pressure  generated. 

To  the  student  it  is  then  apparent  that  changing  any  one  of  these 
three  factors  will  affect  the  output.  Increasing  either  of  the  three 
factors  increases  the  output,  while  the  decrease  of  any  of  the  three 
will  decrease  the  output.  On  the  other  hand,  if  while  one  factor  is 
decreased  one  of  the  two  remaining  factors  is  increased,  the  resulting 
voltage  may  be  maintained  at  the  desired  point.  Counterbalancing 
one  factor  which  is  variable  by  making  another  variable  is  the  prin- 
ciple of  practically  all  regulating  systems.  Th^e  speed  of  the  arma- 
ture as  indicated  above  is  the  factor  which  it  has  been  found  impracti- 


432 


Automotive  Trade  Training 


cal  to  maintain  at  a  fixed  figure.  The  forced  variation  within  it  of 
approximately  4,000  R.  P.  M.  is  counteracted  by  some  device  which 
will  control  the  density  of  the  magnetic  flux.  This  modification  may 
be  effected  in  several  ways,  the  most  usual  of  which  are  the  follow- 
ing: 

Third  brush  control. 

Differential  compound  wound,  or  bucking  series  field. 

Inserted  resistance,  or  vibrating  regulator. 

The  third  brush  control  is  the  most  popular.  Very  frequently, 
however,  it  is  used  in  conjunction  with  some  other  means  of  output 
control.  These  auxiliary  aids  to  the  third  brush  will  be  explained  in 
the  description  of  the  equipment  in  which  they  are  used. 

Inserted  Resistance  or  Vibrating  Relay  Controller. — In  this  case 


hseried 
/fesjst 


Cu/ya/T^  C/rct/ft 


y^/iag&  £>^c^/t~^ 


fliliomcLtiO 
,Cut-oui 


"^^o/Ttacts 


flatomaiic 


&eN^R^TOR 


^/^TTtRy 


Fig.    508.     Inserted     Resistance    Control.     Current    Circuit    used    on    Coil. 
Automatic   Cut-out  in  Circuit. 

che  output  of  the  generator  is  controlled  by  the  magnetic  action  of 
the  vibrating  controller.  The  device  consists  of  a  soft  iron  core  with 
either  a  voltage  or  a  current  coil  wound  on  it.  In  some  cases  it  is 
supplied  with  both.  In  the  latter  case  the  automatic  cut-out  is  in- 
corporated with  the  controller  relay.  The  student  must  not  confuse 
these  two  instruments.  A  casual  glance  would  lead  to  the  conclusion 
that  they  were  the  same  as  each  is  equipped  with  contact  points  held 
in  position  by  a  spring.  In  the  cut-out  the  points  are  normally  open, 
allowing  current  to  flow  only  when  they  are  drawn  together  by  the 
magnetic  action  of  the  core.  Just  the  reverse  is  true  in  the  case  of 
the  relay  controller.  The  points  are  normally  held  together.  When 
the  current  flowing  through  them  becomes  equal  to  the  desired  gen- 
erator output  for  battery  charging  or  lighting  use,  the  action  of  the 
controller  is  so  arranged  that  the  strength  of  the  spring  holding  the 


Starting  Motors  and  Generators 


433 


contacts  together  is  overcome  by  the  magnetic  action  of  the  core  and 
winding,  thus  drawing  the  points  apart. 

As  the  points  separate,  a  bit  of  resistance  wire  is  inserted  into 
the  circuit  which  regulates  the  strength  of  the  field.  The  resistance 
cuts  down  on  the  amount  of  current  permitted  to  flow  to  the  field 
circuit.  As  the  strength  of  the  field  is  thus  decreased,  the  amount 
of  current  generated  within  the  armature  is  necessarily  likewise 
decreased.  As  this  output  is  decreased,  the  magnetic  pull  of  the  con- 
troller core  on  the  soft  iron  part  carrying  the  movable  contact  point 
is  decreased  to  such  a  point  that  the  pull  on  the  spring  is  greater  than 
the  magnetic  pull  and  the  points  return  to  normal  position.  The 
resistance  which  really  controls  the  output  is  thus  cut  in  and  cut  out 
many  times   a   second.     It   is   usually   brought   into   action   at   from 


Carre/fi  Cfrcutt 

^ij      ■    ■  ^  ^a  t-^ut  Coff tacts ^ 


Fig.   509.     Inserted   Resistance   Control.     Voltage  coil  only   used   on   regulator   coil. 
Automatic  Cut-out  in  Circuit. 

fwelve  to  eighteen  miles  per  hour.  The  device  may  be  used  either 
in  connection  with  the  voltage  or  the  amperage  of  the  generator.  If 
the  current  or  amperage  is  depended  on,  the  controller  core  is  wound 
with  wire  heavy  enough  to  carry  the  entire  output  of  the  generator. 
If  voltage  or  pressure  is  depended  on  for  regulation,  the  wire  may 
be  very  light  and  the  ends  of  it  connected  across  the  generator 
brushes  in  a  plain  shunt. 

The  student  does  not  want  to  lose  sight  of  the  fact  that  the  out- 
put of  the  generator  is  actually  controlled  by  the  inserted  resistance 
and  that  the  relay  is  made  to  insert  and  withdraw  this  resistance 
automatically,  and  in  such  degree  that  the  amount  of  current  flowing 
to  the  battery  and  lighting  circuit  is  maintained  at  a  uniform  value 
no  matter  what  the  operating  speed  of  the  engine.  As  the  field  builds 
up,  the  output  increases.    Armature  speed,  one  of  the  three  controll- 


434 


Automotive  Trade  Training 


Cui-Oat  Cofiiach 


Fig.    510.     Inserted    Resistance    Control.     Cut-out    and    Regulator    combined    with    both 
current  and  voltage  coils  assisting  in  the  operation  of  each  part  of  instrument. 

ing  factors,  is  responsible,  as  part  of  the  current  taken  off  from  the 
armature  through  the  brushes  is  shunted  into  the  field  to  build  that. 
Consequently,  to  offset  the  speed  factor  the  magnetic  field  strength 
is  decreased  by  preventing  the  return  to  the  field,  w^inding  the  normal 
proportion  of  armature  output.  The  insertion  of  the  resistance 
accomplishes  this. 

As  stated  before,  the  usual  practical  application  of  this  method 
is  through  the  combination  of  the  automatic  cut-out  and  vibrating 
relay.  Both  w^indings,  the  heavy  current  circuit  and  the  light  or 
fine  w^inding  shunted  across  the  brushes,  thus  influence  the  action  of 
the  instrument.  As  the  voltage  starts  building  up  when  the  genera- 
tor is  driven  by  the  engine,  the  cut-out  points  are  closed.  When 
closed  the  current  starts  flow^ing  through  the  current  winding  to  the 
battery.  This  adds  to  the  magnetic  pull  affecting  the  closing  of  the 
cut-out  points  and  helps  to  hold  them  securely  together.  Both  coils 
acting  together,  since  they  are  wound  on  the  core  in  the  same  direc- 
tion, affect  the  action  of  the  vibrating  points.  The  spring  tension 
controlling  the  separation  of  these  points  is  regulated  to  increase  or 
decrease  the  output  of  the  machine.  Increasing  tlie  tension  on  the 
spring  means  that  more  current  must  flow  at  a  higher  voltage  before 
the  contacts  open  and  the  resistance  is  inserted.  Decreasing  the 
tension  on  the  spring  means  that  there  is  less  voltage  and  less  current 
flow  required  to  separate  the  points  and  insert  the  resistance.  As  a 
consequence  the  output  is  increased  or  decreased  at  the  desire  of  the 
mechanic. 

Differential  Compound  Wound  or  Bucking  Series  Field. — It  is 
presumed   that   the   student   is    familiar   with    the   terms   shunt    and 


Starting  Motors  and  Generators 


435 


series  as  applied  to  the  winding  of  generators  and  motors.  The 
action  of  the  type  of  regulation  depending  on  the  bucking  series  field 
is  easily  understood  if  it  is  remembered  that  winding  an  electro- 
magnet with  many  turns  of  wire  will,  when  current  is  sent  through 
the  wire,  make  one  end  of  the  electrom.agnet  north  and  the  other 
end  a  south  pole.  Reversing  the  direction  of  the  winding  will  reverse 
the  polarity.  That  is  the  pole  formerly  north  is  then  a  south  pole, 
and  vice  versa.  If,  on  the  other  hand,  a  number  of  turns  of  wire  are 
wound  on  in  one  direction  and  then  the  direction  of  winding  is 
reversed  and  a  like  number  of  turns  put  on  in  the  opposite  direction, 
it  is  evident  that  there  will  be  a  bucking  effect  between  the  two  coils 


GENERATOR 


Fig.  511.     Bucking  Series  Field  with  Automatic  Cut-out  in  Circuit. 

as  the  current  is  run  through  them.  One  coil  would  attempt  to  make 
a  north  pole  out  of  a  certain  end  of  the  core,  while  the  other  coil 
would  attempt  to  make  the  same  end  into  a  south  pole.  If  the  coils 
were  just  equal  there  would  be  a  complete  neutralization  of  the 
magnetic  effect  and  there  would  be  no  decided  polarity  evident.  The 
magnetic  field  or  flux  would  be  destroyed. 

In  the  bucking  series  field  regulation  this  is  the  basis  of  the  con- 
trol. Part  of  the  output  of  the  armature  is  run  through  the  field  to 
build  it  up.  This  is  called  a  shunt  field.  If  all  the  current  passing 
through  the  armature  winding  were  passed  through  the  field  that 
would  be  series  winding.  In  this  case  the  shunt  winding  which  is 
the  longest  is  wound  in  one  direction  about  the  pole  shoes  to  form 
the  electromagnet  and  set  up  the  magnetic  field.  The  charging  cur- 
rent also  taken  from  the  armature  brushes  is  run  about  the  pole  shoes 
in  the  opposite  direction  in  its  circuit,  and  before  it  is  carried  through 
the  automatic  cut-out  and  ammeter  to  the  battery. 

Consequently,  as  the  output  grows,  more  and  more  current  will 
pass  around  the  pole  shoes  in  the  opposite  direction  to  that  building 


436 


Automotive  Trade  Training 


up  the  field.  This  current  bucks  or  neutralizes  the  magnetic  flux  or 
field  by  attempting  to  build  up  a  field  of  reversed  polarity,  with  the 
result  that  the  stronger  field  is  bucked  or  partially  neutralized.  Since 
the  magnetic  field  is  one  of  the  determining  factors  of  all  generators 
it  vi^ill  be  seen  that  the  neutralization  of  part  of  the  field  will  cause  a 
falling  off  of  the  output.  The  increased  output,  due  to  higher  arma- 
ture speeds,  is  used  to  neutralize  the  field  and  reduce  itself.  As  in 
the  case  of  the  vibrating  controller  the  increase  of  armature  speed, 
which  is  one  of  the  three  factors,  is  offset  by  a  decrease  of  the  mag- 


1 

h 

r/V//?Z7  BffL/SH 

3 

R^GULRTION 

\\ 

n 

5 

ANGLE  OF  F1.UX 

V 

5 

OlSTORTlONv 

i     V 

z 

H 

■^  \  ' 

2} 

1                          \ 

ANGLE  OF  FLUX                           ]          ^ijX            \ 

5 

DISTORTION                                    [          ^    oX       V'^ 

i 

z 

H 

ARMATURE  REACTION  COMP< 

5NENT 

ARMATURE  REACTION  COMF 

►QiiENT 

Pig.  512. 


Parallelograms  illustrating  degree  of  flux  deflection  due  to  the  armature 
reaction. 


netic  field  factor.  The  same  result  is  accomplished  by  different 
means.  This  method  entails  no  moving  parts.  There  is  no  method 
of  readily  increasing  or  decreasing  the  output.  If  the  circuit  used  to 
charge  the  battery  and  light  the  lamps  should  fail  for  any  reason  no 
current  would  be  traveling  in  the  reverse  direction  to  buck  down  the 
shunt  field  circuit.  This  would  permit  the  voltage  to  build  up  and  up 
until,  if  the  car  were  operated  at  considerable  speed  the  field  and 
voltage  coil  on  the  cut-out  would  most  certainly  be  burned  and  dam- 
aged. Consequently  great  care  must  be  used  to  see  that  all  terminals 
are  tight  and  the  wiring  complete. 

Third  Brush  Control. — In  this  system  which  is  used  to  a  greater 
extent  than  any  other  the  governing  factor  is  the  armature  reaction. 
When  the  electric  current  flows  through  the  coils  of  the  armature 
as  it  is  generated  it  magnetizes  the  iron  core  of  the  armature.     This 


Starting  Motors  and  Generators 


437 


magnetism   is  termed   cross   magnetism   and  affects   the  main   field 
magnetic  flux. 

With  the  main  magnetic  field  established  at  full  strength  by  the 
exciting  current  flowing  through  the  field  coils,  the  lines  of  force  will 


BTARTING 
SWITCH 


Fig.  513.     Starter  Generator  not  in  operation.     Third   Bush   Control. 


Fig.  514.     Starter  Generator  running  at  1200  R.  P.  M.     Third  Brush  Control. 

leave  the  north  pole,  pass  across  the  first  air  gap  to  the  armature, 
through  the  armat]^re  to  the  second  air  gap,  and  across  it  to  the  south 
pole.  If  the  armature  is  not  in  motion  and  no  current  is  flowing 
through  its  coils  to  set  up  the  cross  magnetization,  the  lines  of  force 
pass  across  from  the  north  to  the  south  pole  in  a  straight  path. 
However,  with  cross  magnetization  present,  the  armature  flux  thus 


438 


Automotive  Trade  Training 


produced  creates  a  secondary  field  having  a  marked  influence  on  the 
main  field. 

This  cross  magnetization  is  at  right  angles  to  the  lines  of  force 
flowing  in  the  main  field.     It  is  this  fact  that  is  relied  on  to  control 


Fiei.D  Current. 

23    AMPCRES 


Fig.  515.     Starter  Generator  running  at  2200  R.  P.  M.     Third  Brush  Control. 


nCUa  CURRENT 
'1.25   AnPOK» 


Fig.  516.     Starter  Generator  running  at  5000  R.   P.  M,     Third  Brush   Control. 

the  field  flux  and  consequently  the  generator  output.  It  is  a  well 
known  fact  that  two  forces  coming  together  at  an  angle  will  result 
in  the  combined  force  following  a  line  which  is  that  of  neither  of  the 
first  two  forces.  If  the  two  forces  are  equal  the  angle  of  distortion 
will  be  such  as  to  bring  the  line  of  the  new  force  half  way  between 


Starting  Motors  and  Generators 


439 


the  two  originals.  However,  if  there  is  one  weaker  than  the  other 
the  line  of  distortion  will  form  a  smaller  angle  with  the  line  of  the 
main  force  than  if  they  were  equal.    Refer  to  Fig.  512. 

In  the  application  of  this  principle  to  the  generator  the  main  lines 


SHUNT  ricuo  COIl_- 


^   POI_E    STARTER -GENERATOR 
RUNNING    AT   aaOO    R.P.M. 

rzzzzzi 


SERIES  riCUO  COIL.- 


+   MAJN  BRUSH 


—  MAIN  BRUSH 


omitted" 
+  main  brush 


"OMITTED" 
—   MAIN  BRUSH 


3RO   BRUSH 


J 


Fig.    517.     Wiring    Diagram    showing   Dodge    Northeast    Starter    Generator    operating    at 

average  speed. 


of  force  are  those  passing  from  the  north  to  the  south  pole  shoes. 
The  distorting  force  is  the  armature  flux.  When  the  generator  is 
idle  or  just  starting  to  generate  this  force  is  negligible.  However,  as 
the  output  increases,  the  force  tending  to  distort  the  field  flux  also 
increases.     As  this  force  grows  stronger  and  stronger,  the  main  flux 


440  Automotive  Trade  Training 

is  distorted  more  and  more.  When  the  main  field  flux  is  distorted 
fewer  Hnes  of  force  are  cut  by  the  armature  conductors  when  in  such 
position  that  the  current  can  be  taken  off  by  the  brushes.  This 
results  in  a  decrease  of  the  output  with  the  result  that  the  cross 
magnetization  and  main  flux  distortion  are  also  less.  Again  the  out- 
put is  made  to  regulate  itself  by  decreasing  the  strength  of  the  field, 
the  same  as  in  the  case  of  the  vibrating  regulator  and  the  bucking 
field  types  of  regulation.  The  part  the  third  brush  plays  is  illustrated 
in  Fig.  517.  The  third  brush  is  at  the  point  of  greatest  voltage  value 
with  reference  to  the  armature  coils.  The  armature  reaction  results 
in  the  greatest  armature  value  being  thrust  to  one  side  of  the  third 
brush.  Since  the  third  brush  takes  the  current  from  the  armature 
which  is  used  to  excite  the  field,  it  is  evident  that  not  as  much  cur- 
rent will  be  taken  off  by  it  when  the  distortion  is  greatest,  thus  result- 
ing in  a  decrease  of  the  field  flux. 

The  speed  factor  again  attempts  to  build  up  the  armature  output. 
Because  of  armature  reaction  and  the  third  brush  location  the  speed 
factor  is  offset  by  the  weakened  field  factor. 

There  are  many  variations  of  these  three  types  of  regulation,  but 
the  main  principles  involved  have  been  explained.  The  variations  in 
certain  instruments  are  described  under  their  respective  job  sheets. 

Cut-Out  Relay. — The  cut-out  relay  is  an  automatic  switch  in- 
serted in  the  charging  circuit.  The  construction  may  be  noted  in  a 
number  of  the  illustrations,  for  example  Fig.  511.  Not  all  systems 
utilize  the  automatic  cut-out.  A  number  of  Delco  systems  have  had 
the  cut-out  switch  in  connection  with  the  ignition  switch  so  that 
when  the  ignition  takes  place  the  generator  will  start  motoring  and 
continue  doing  so,  drawing  current  from  the  battery  until  the  genera- 
tor speed  is  sufficient  to  produce  an  output  and  voltage  greater  than 
the  battery  voltage,  at  which  point  the  generator  starts  charging  the 
battery.  Turning  off  the  ignition  also  turns  off  the  generator  cur- 
rent and  breaks  the  charging  circuit. 

The  automatic  cut-out  switch  is  dependent  on  the  voltage  coil 
shunted  across  the  generator  brushes,  to  make  contact,  or  bring  to- 
gether the  cut-out  points.  This  is  due  to  the  magnetic  pull  of  the 
cut-out  core  which  is  made  of  soft  iron.  The  magnetic  pull  is  resisted 
by  the  spring  tension.  The  strength  of  the  spring  must  be  such  that 
it  will  hold  the  points  open  until  the  generator  voltage  is  slightly 
more  than  that  of  the  battery.  Under  this  condition,  when  the  points 
are  closed,  the  current  will  flow  immediately  to  the  battery  to  charge 
it  and  no  discharge  is  possible.  Referring  to  Fig.  511  the  student 
will  note  that  the  current  coil  is  wound  on  the  core  in  the  same 
direction  as  the  voltage  coil.  Accordingly  when  the  contact  points 
close  the  magnetic  pull  of  the  iron  core  is  increased  and  the  switch 
is  made  all  the  more  positive  in  action. 


Starting  Motors  and  Generators  441 

The  student  must  not  confuse  the  vibrating  control  points  with 
the  cut-out  points.  The  latter  remain  closed  ouce  the  generator  speed 
assures  a  sufficient  voltage  until  the  speed  of  the  generator  drops  too 
low  when  they  are  automatically  opened.  The  regulator  points,  on 
the  other  hand,  vibrate  rapidly,  alternately  inserting  and  cutting  out 
the  inserted  resistance  which  is  used  to  regulate  the  magnetic  field, 
and  consequently  the  generator  output. 

Since  the  cut-out  is  closed  automatically,  it  must  likewise  be 
designed  to  open  automatically.  When  the  voltage  builds  up  to  a 
certain  point  the  contacts  close  and  current  flows  as  stated  previously 
until  the  generator  speed  falls  below  the  point  where  the  voltage  is 
below  that  of  the  battery.  When  this  happens  the  current  starts 
flowing  not  from  the  generator,  but  from  the  battery  to  the  genera- 
tor. This  reversal  of  current  in  the  charging  circuit  attempts 
to  reverse  the  polarity  of  the  cut-out  core  and  in  so  doing  neu- 
tralizes the  current  flowing  through  the  voltage  coil  which  has 
no  connection  to  the  battery.  In  this  manner  the  pull  of  the  iron 
core  is  neutralized  and  the  spring  pulling  on  the  contact  causes  it 
to  be  opened  immediately.  If  the  engine  is  being  stopped  the  points 
remain  open.  However,  if  the  engine  has  slowed  only  momentarily, 
the  points  will  close  immediately  the  car  and  engine  speed  again 
passes  the  predetermined  point,  about  seven  to  ten  miles  per  hour. 

The  entire  purpose  is  to  automatically  switch  on  and  off  the 
charging  circuit  in  such  manner  that  no  attention  need  be  given  to 
the  act  by  the  operator  of  the  machine.  Occasionally  the  cut-out 
points  will  stick.  If  this  happens,  the  battery  will  be  discharged  back 
through  the  generator.  Where  the  system  is  equipped  with  an 
ammeter  this  fact  may  be  detected  by  its  action.  The  hand  would 
stand  at  possibly  ten  to  twenty  amperes  discharge  with  the  lights 
and  ignition  oflf.  Points  will  stick  because  they  are  burned  by  an 
excessive  charge,  or  because  of  failure  of  the  spring  or  other  mechani- 
cal parts. 

JOB  150.     WAGNER  STARTING  MOTOR. 

As  used  on  the  Studebaker  cars  the  Wagner  starting  motor  is  rather 
representative  of  the  entire  Wagner  line.  The  machine  illustrated  in  Fig.  518 
utilizes  reduction  gears  to  cut  down  the  speed  and  increase  the  cranking  power. 
A  further  reduction  of  speed  and  increase  of  power  is  secured  through  the  use 
of  a  small  sprocket  on  the  starter  gear  shaft  and  a  larger  one  on  the  crank- 
shaft of  the  engine.  This  latter  is  mounted  on  the  forward  end  of  the 
crankshaft  and  includes  an  over-running  clutch  in  the  hub  on  which  it  is 
mounted  as  part  of  the  starting  equipment.  This  clutch  allows  the  engine  to 
drive  faster  than  the  starting  motor  once  it  begins  to  operate  under  its  own 
power.  The  Wagner  line  includes  the  popular  bendix  drive  as  well  as  the 
reduction  gear  chain  and  sprocket  types  mentioned  above.  Fig.  520  illustrates 
a  bendix  drive  gear  reduction  combination,  built  by  the  same  company. 

The  single  unit  method  of  construction  is  employed  in  all  Wagner  equip- 
ment.   A  particular  item  of  interest  is  the  size  of  the  starting  motors.    These 


442 


Automotive  Trade  Training 


Fig.  518.    Wagner  Starting  Motor, 
are  always  small  and  light.     Through  proper   design  and   gear  reduction   the 
very  small  instrument  has  proven  equal  to  the  task  of  readily  spinning  heavy 
six  cylinder  engines  even  under  adverse  starting  conditions. 

Starting  Switch. — From  the  car  wiring  diagram,.  Fig.  557,  it  may  be  noted 


Pig.  519.    Light  and  powerful  starting  motor,   driving  through  chain  and  over-running 

clutch   (Studebaker). 

that  a  large  cable  from  the  negative  side  of  the  battery  is  fastened  to  one  side 
of  the  starter  switch.  This  switch,  shown  dismantled  in  Fig.  521,  is  of  the 
plunger  type.  It  is  so  arranged  that  when  the  plunger  is  depressed  it  makes 
contact  with  the  two  copper  contact  segments  located  in  the  base  of  the  switch 


Fig.  520.    Wagner   Starting  Motor  with  Bendix  Drive. 


Starting  Motors  and  Generators 


443 


connecting   them,  thus   providing  a   closed   circuit   from  the   battery   to   the 
starting  motor. 

In  case  of  any  trouble  with  the  switch  it  should  be  disassembled  and 
cleaned.  If  the  springs  on  the  plunger  have  become  bent  out  of  shaf)e  they 
should  be  repaired  by  springing  until  they  will  make  firm  contact.  Be  very 
certain  not  to  harm  or  displace  the  insulating  materials,  otherwise  short 
circuits  will  develop  and  cause  battery  and  starter  trouble. 


Fig.   521.    Wagner    Starting    Switch. 


JOB  151.     BUICK  DELCO  MOTOR  GENERATOR. 

Motor  Generator  Operation. — The  motor  generator  performs  the  three 
following  operations: 

1.  Motoring  the  Generator. — This  operation  is  necessary  in  order  that  the 
starting  gears  may  be  brought  in  mesh  with  the  small  gear  on  the  armature 
shaft  and  with  the  teeth  in  the  fly  wheel.  This  motoring  of  the  generator 
takes  place  whenever  the  lever  on  the  left-hand  side  of  the  ignition  switch  is 
turned  to  position  marked  "On,"  thus  completing  the  circuit  from  the  battery 
to  the  generator  windings.  This  discharge  of  current  is  through  the  shunt 
field  windings  and  the  generator  windings  on  the  armature.  The  motoring 
speed  of  the  generator  is  slow. 

2.  Cranking  Operation. — The  cranking  operation  is  performed  when  the 
starting  gears  are  brought  fully  in  mesh  and  the  motor  brush  makes  contact 
with  the  commutator.  The  brush  thus  brought  into  contact  with  the  com- 
mutator after  the  gears  are  properly  meshed  serves  the  same  purpose  as 
closing  a  switch.  A  heavy  current  flows  from  the  battery  to  the  starter 
windings  of  the  machine.  It  is  very  essential  that  all  parts  such  as  brushes, 
terminals,  etc.,  make  good  electrical  contact. 

3.  Generating  Operation. — After  the  engine  has  been  cranked  and  starts 
to  operate  under  its  own  power,  the  starting  pedal  is  returned  to  its  normal 
position  by  a  spring  action.  This  demeshes  the  starting  gears,  at  the  same 
time  raising  the  starting  motor  brush  from  the  starting  motor  commutator, 
and  lowers  the  generator  brush  onto  the  generator  commutator  from  which  it 
is  always  lifted  while  cranking  the  engine.  At  very  low  speeds  the  voltage 
generated  is  not  sufficient  to  overcome  the  voltage  of  the  storage  battery,  and 
a  small  amount  of  current  may  be  discharged  from  the  battery  through  the 


444 


Automotive  Trade  Training 


generator  winding.  At  all  normal  engine  speeds  the  voltage  of  the  generator 
is  sufficient  to  overcome  that  of  the  battery  and  the  current  flows  through  the 
battery  and  recharges  it. 

The  ammeter  on  the  dash  registers  the  rate  at  which  the  storage  battery 
is  discharging,  or  the  rate  at  which  the  generator  is  charging  the  battery. 

Current  Control  and  Output  Regulation. — The  current  control  is  eiTected 
by  the  third  brush  system  of  regulation.  To  regulate  the  output  the  brush 
must  be  moved  to  the  right  or  left  as  indicated  in  Job  156. 


Starting  Motors  and  Generators 


445 


xr>j/  (h-^ 


446  Automotive  Trade  Training 

JOB  152.  DODGE  NORTHEAST  MOTOR  GENERATOR. 

The  instrument  which  is  of  the  single  unit  type  is  mounted  on  the  left-hand 
side  of  the  engine.     It  is  driven  by  the  engine  at  three  times  the  engine  speed. 
It  operates  directly  from  the   crankshaft  through  a   silent  chain   drive.     The 
machine  employs  only  one  commuta- 
tor,  one   set   of   field   windings,   one 
set  of  brushes,  and  one  armature  for 
the  performance  of  all  its  functions 
both  as  a  starting  motor  and  gener- 
ating dynamo. 

Starting  Characteristics. — While 
starting  the  engine  the  instrument 
acts  as  a  cumulatively  compounded 
motor,  but  while  serving  as  a  gener- 
ator it  serves  as  a  dififerentially  com- 
pounded machine  with  its  output  ^^^-  ^24 
positively  controlled  by  means  of  the  third  brush  regulating  system,  supple- 
mented by  the  differential  influence  of  the  series  field  upon  the  shunt  field. 

Generating  Characteristics. — The  machine  is  designed  for  twelve-volt 
service.  When  driven  by  the  engine  it  normally  begins  to  deliver  current  to 
the  battery  as  soon  as  the  engine  speed  is  brought  to  a  speed  corresponding 
to  a  ten  miles  per  hour  car  speed.  At  a  car  speed  of  sixteen  to  seventeen  miles 
per  hour  the  standard  maximum  output  of  six  amperes  is  reached.  This  rate 
will  remain  practically  constant  until  a  car  speed  of  twenty  to  twenty-one 
miles  is  reached,  after  which  the  charging  rate  will  decrease  gradually  until 
at  the  upper  speed  limit  of  the  engine  it  may  be  as  low  as  three  amperes. 
Whenever  abnormal  driving  conditions  are  encountered,  some  special  care  to 
take  proper  account  of  them  may  be  needed. 

Correcting  Overcharge.— Where  the  battery  seems  to  show  a  tendency  to 
be  chronically  overcharged  the  condition  may  be  relieved  by  allowing  the 
lamps  to  burn  dim  for  five  or  six  hours  to  reduce  the  charge.  To  reduce  the 
charge  quickly  it  is  a  safe  plan  to  permit  the  battery  to  crank  the  engine  from 
five  to  ten  minutes  until  the  charge  is  materially  reduced.  In  some  cases  the 
lamps  may  be  burned  dim  while  the  car  is  left  in  the  garage  over  night. 

Correcting  Undercharge. — Undercharge  may  be  corrected  by  having  the 
battery  charged  at  a  service  station,  or  by  driving  the  generator  with  the 
engine  while  the  car  is  standing.  Refer  to  Chapter  11  on  battery  charging, 
for  instruction  in  charging  by  other  methods. 

If  too  much  trouble  is  experienced  in  keeping  the  battery  in  proper 
condition,  the  charging  rate  may  be  decreased  or  increased  by  regulating  the 
third  brush.  In  making  any  change  of  the  third  brush  setting  the  charging 
rate  must  not  be  permitted  to  become  less  than  four  amperes  nor  more  than 
ten  as  a  maximum  figure. 

Method  of  Readjusting  Starter  Generator  Output. — The  student  must 
always  bear  in  mind  the  difference  between  charging  rate  and  generator  output. 
The  latter  is  the  entire  amount  of  the  current  producd  by  the  machine,  while 
the  charging  rate  varies  considerably.  This  variation  is  due  to  the  fact  that 
the  ignition  always  consumes  part  of  the  output  and  when  the  lamps  are 
burning  they  may  consume  nearly  the  entire  output.  At  these  times  then  the 
battery  is  charged  by  that  portion  of  the  output  which  is  left  after  the  normal 
needs  of  the  electric  system  are  supplied.  Knowing  these  facts,  it  is  easy  to 
see  how  the  poor  driver  may  easily  exhaust  the  battery  by  continued  cranking, 
or  how  the  driver,  who  uses  his  car  a  great  deal  at  night  for  short  drives, 
will  encounter  the  same  trouble.     On  the  other  hand,  the  careful  driver  will 


Starting  Motors  and  Generators 


447 


conserve  the  energy  within  his  battery  by  properly  setting  his  spark  and 
throttle  before  cranking.  A  driver  doing  much  touring  in  the  daytime  will 
likely  find  a  tendency  to  overcharge  the  battery.  If  the  remedial  measures 
mentioned  above  are  not  satisfactory  and  the  charging  rate  must  be  changed 
proceed  as  follows: 


ftHUNT  nCLO 


ClOHTINa 

«  MNITION 

SWITCH 


tJATTERY 


CROUND 


Fig.  525.     Circuit   Diagram   of  the   North   East  ]\Iodel  G    Starting  and   Lighting   System. 

Type  3566  Starter-Generator.     Type  8100   Starting   Switch   and   Reverse 

Current  Cut-Out. 


1.  With  the  starter  generator  in  position  to  run  either  on  the  car  or  on  a 
test  bench,  insert  a  suitable  ammeter  in  circuit  to  read  the  total  output.  Also 
connect  a  voltmeter  capable  of  reading  at  least  twenty  volts  across  the  two 
binding  posts  of  the  starter-generator  to  read  the  generated  voltage. 

2.  Run  the  starter-generator  at  1800  R.  P.  M. — the  speed  at  which  its 
maximum  output  is  normally  delivered — and  note  the  readings  of  the  am- 
meter and  the  voltmeter. 

3.  Consult  the  output  table,  page  449,  and  compare  the  current  and  voltage 
readings  obtained  in  the  test  with  those  given  in  the  table.  In  doing  this 
take  into  consideration  the  output  variations  that  occur  as  the  result  of  changes 
in  the  counter-electromotive  force  (back-voltage)  of  the  battery.  To  take 
these  variations  properly  into  account,  first  ascertain  the  approximate  C.  E.  M. 
F.  of  the  battery  by  measuring  the  starter-generator  termnal  voltage,  which  is 
its  practical  equivalent;  and  then,  referring  to  the  table,  compare  the  observed 
current  reading  with  the   corresponding  standard   value  of   current   to   be   ex- 


448 


Automotive  Trade  Training 


Fig.  526.    The   North   East   Model   G    Starting:  and    Lighting   System   as   applied   to    the 

Dodge   Bros.  Motor  Car. 


pected  at  the  actual  voltage  in  question.  Should  the  test  reading  be  thus 
found  to  differ  from  the  equivalent  standard  reading,  due  allowance  for  the 
fact  must  be  made  in  re-adjusting  the  machine. 


Starting  Motors  and  Generators 


449 


Variations  in  Starter-Generator  Output  Due  to  Changes  in  Battery  C.  E.  M.  F. 

Starter-Generator  Output  Battery  C.  E.  M.  F.  Starter-Generator 

(Starter-Generator  Terminal  E.  M.  F.) 

Amperes  Volts  R.  P.  M. 

5.5  12  1800 

6  13  1800 
6.5  14  1800 

7  15  1800 
7.5  16  1800 


PORTABLE 
AMMETER 


1R£VERSE'CURRE>IT 
CUT-  OUT       ^A 
TO 


TO 
UIGiHTINQ 
9t  IQNITION 


,  /+  BATTERY  & 
\-  INDICATOR 

Fig.  527.    Ammeter  Counections  for  taking  Output  Readings. 

4.  Refer  to  Fig.  528  showing  the  Brush  Rigging.  After  ascertaining  the 
true  output,  shift  the  position  of  the  third  brush  until  the  required  modifica- 
tion in  the  setting  is  obtained.  This  is  to  be  done  in  the  following  manner: 
Release  the  third  brush  plate  clamp  (8757)  by  backing  off  the  clamp  screw 
(4069)  one  or  at  most  two  turns.  Then  turn  the  adjusting  pinion  stud  (8035) 
slowly  until  the  desired  output  is  registered  by  the  ammeter.  The  stud  should 
be  turned  in  a  counter-clockwise  direction  to  reduce  the  output,  and  in  a 
clockwise  direction  to  increase  it.     The  output  must  never  be  reduced  below 


MAIN   BRUSH 
COPPER  COUOREO 


8039 

THIRD  BRUSH 


Fig.  528.     Dodge  Northeast  Brush   Rigging. 


450 


Automotive  Trade  Training 


a  value  equivalent  to  four  amperes  at  1800  R.  P.  M.  at  a  battery  C.  E.  M.  F. 
of  fifteen  volts,  nor  must  it  be  raised  above  a  maximum  equivalent  to  ten 
amperes  at  the  same  battery  voltage.  As  soon  as  the  proper  setting  is  ob- 
tained, lock  the  third  brush  plate  again  by  tightening  the  clamp  screw.  Then 
as  a  precautionary  measure  against  having  disturbed  the  setting  while  lock- 
ing the  clamp,  note  the  instrument  readings  once  more  after  all  adjustments 
have  been  secured. 

5.  Before  the  operation  is  to  be  considered  finished,  the  starter-genera- 
tor, must  be  given  a  final  test  by  running  it  for  fifteen  or  twenty  minutes  at  a 
constant  speed  of  1800  R.  P.  M.  During  this  time  the  readings  of  both  the 
instruments  should  be  watched  closely  to  make  sure  that  the  new  setting  is 
accurate  and  permanent.  The  machine  should  then  be  subjected  to  a  brief 
varying  speed  test  by  first  lowering  its  speed  to  700  or  800  R.  P.  M.  and  then 
raising  it  to  approximately  3000  R.  P.  M.  Finally  a  general  inspection  of  the 
entire  equipment  should  be  made  to  see  that  no  other  parts  have  been  dis- 
turbed while  the  output  re-adjustment  was  being  made. 


^■j 

W/gftKtttifttfttl^Kt 

p 

m\    M^^t-^"           ,..     Jk"-':^'^^ff^*"'*^ '- 

1              •  #     C» 

V.:V    ■?                /                                                                                   A 

w 

Fig,  529.     Dyneto  "KIR"  Motor  Generator,  as  used  by  H.  H.  Franklin  Mfg.  Co. 


JOB  153.     DYNETO  SYSTEM  AS  USED  ON  THE  FRANKLIN  CAR. 

The  Dyneto  System  is  of  the  single  unit  type.  A  light  weight  efficient 
motor  is  permanently  connected  to  the  engine  by  means  of  a  silent  chain 
drive  which  operates  the  generator  at  two  and  one-half  to  three  times  engine 
speed.  The  student  will  want  to  note  this  feature  individual  to  this  system. 
No  over-running  clutch  is  used  to  secure  a  starting  hold  for  the  starting  motor. 
Neither  is  there  a  cut-out  employed.  The  entire  system  consists  of  the  starter 
generator,  a  twelve-volt  battery,  and  the  switch.  The  three  units  are  connected 
by  a  very  simple  wiring  system  consisting  of  two  wires  from  the  motor  gener- 
ator to  the  switch,  one  wire  to  the  battery,  and  one  wire  from  the  battery  to 
the  switch. 

Operation. — The  switch  shown  in  Fig.  530  should  be  placed  on  "start." 
It  is  left  in  this  position  unless  the  battery  is  fully  charged,  or  if  the  car  is 
being  used  for  long  or  fast  runs,  in  which  cases  the  switch  lever  is  moved 
back  to  "neutral"  and  left  there.  With  the  switch  on  "start,"  the  Dyneto 
operates  as  a  starting  motor  spinning  the  engine  from  125  to  200  R.  P.  M. 
After  the  engine  starts  to  run  under  its  own  power  and  above  a  speed  corres- 
ponding to  car  speeds  of  seven  to  eight  miles  per  hour  the  voltage  generated 
is  greater  than  that  of  the  battery  and  flows  to,  rather  than  from,  the  battery 
thereby  charging  it.  Whenever  the  car  speed  drops  below  seven  or  eight 
miles  per  hour,  the  voltage  from  the  battery  overcomes  that  of  the  generator, 
and  the  current  flows  into  the  machine  from  the  battery  causing  it  to  motor 


Starting  Motors  and  Generators 


451 


and  help  drive  the  car.  At  extremely  low  car  speeds  the  system  prevents 
the  motor  from  becoming  stalled.  The  lower  the  car  speed  the  more  power 
available  from  the  Dyneto  system. 

Construction  and  Care. — The  bearings  are  of  the  ann- 
ular ball-bearing  type.  Keep  them  clean  and  apply  a  little 
oil  each  week.  The  brushes  are  mounted  in  their  holders 
which  are  in  turn  mounted  on  a  molded  bakelite  rocker 
arm.  This  is  accessible  through  a  large  hand  hole  pro- 
vided for  the  purpose. 

All  parts  about  the  unit  should  be  kept  clean  and  all 
connections  tight.  The  brushes  should  be  examined  once 
in  a  while.  If  the  commutator  is  dirty  and  causes  sluggish 
action  of  the  starter  it  should  be  cleaned  with  a  piece  of 
fine  sandpaper.  Clean  the  brushes  in  gasoline.  In  replac- 
ing them  they  must  be  returned  to  their  original  holder  and  their  exact  former 
position.  Do  not  place  with  the  wrong  side  up  or  they  will  not  fit  the  com- 
mutator.    Replace  worn-out  brushes  with  Dyneto  brushes  only. 

Failure  to  Start. — If  the  unit  will  not  operate,  turn  off  the  switch,  and 
turn  on  the  lights.  If,  on  attempting  to  start  with  the  lights  on,  they  do  not 
dim,  this  is  an  indication  of  an  open  circuit  in  the  starting  wires.  Examine 
switch  connections,  terminals  and  brushes;  also  the  battery.  If  there  is  a  drop 
in  the  brilliance  of  the  lamps  and  the  dyneto  system  fails  to  start,  the  trouble 
may  be  due  to  loose  connections,  a  rough  or  dirty  commutator,  brushes  worn- 
out  or  not  well  fitted  to  the  commutator,  weak  springs,  grounded  or  defective 
armature  or  field  windings.  Refer  to  tests  in  Job  160  to  Job  188  to  learn 
method  of  tracing  out  trouble, 

Failure  to  Generate. — The  trouble  will  probably  be  found  in  an  open  shunt 


Fig.    530.      Franklin 
Dyneto   Switch. 


Fii?.    531.     Franklin    Engine    with    Dyneto    Electrical    Equipment. 


452 


Automotive  Trade  Training 


field  circuit.  In  Fig.  533,  showing  the  wiring  diagram,  the  circuit  may  be 
traced  out  from  the  negative  pole  of  the  battery  to  post  1,  through  half  of  the 
series  winding  to  the  negative  brush,  through  a  part  of  armature  winding  to 
the  third  brush,  through  the  shunt  field  winding  to  post  3,  through  the  starting 
switch,  if  there  is  one,  to  the  positive  side  of  the  battery.  The  shunt  circuit 
mentioned  above  may  be  tested  independently  of  the  main  circuit  by  removing 
the  wire  from  post  2  so  as  to  cut  out  the  main  armature  circuit,  and  setting 
the  starting  switch  on  start.  If  the  shunt  circuit  is  complete  a  bright  spark 
will  be  made  when  the  wire  is  removed  from  post  3.  If  no  spark  occurs,  look 
over  all  the  wires  and  connections  and  an  open  circuit  will  be  found.  Conned 
the  ammeter  for  this  test  as  shown  in  the  illustration. 


CUT  OUT 


FRAME 


%^ 


COVER  FELT  CASKET 

3rd  OR  RECULATtNG  BRUSH 
BRUSH  YOKE      I     BEARING  ARMATURE 


-BEARING 


Fig.  532.    Gray  &  Davis  Generator  and  Cut-Out. 
JOB   154.     GRAY  AND   DAVIS   GENERATOR  AND    CUT   OUT. 


Dynamo  (Generator). — The  dynamo  is  of  the  shunt  wound  type,  and  is 
thus  classified  because  its  field  windings  are  connected  in  shunt  with,  or 
across,  the  armature.  The  fields  are  connected  in  series,  one  side  being  con- 
nected to  the  positive  brush  and  the  other  to  the  third  or  regulating  brush. 

The  third  brush  system  of  regulation  is  used,  thus  insuring  protection  to 
the  battery  and  lamps  at  high  operating  speeds.  The  dynamo  cut-out  is  shown 
in  Fig.  532  as  it  is  mounted  inside  the  machine.  It  closes  the  circuit  when  the 
dynamo  output  is  great  enough  and  opens  the  circuit  when  the  generating 
speed  is  insufficient  to  charge  the  battery.  The  shunt  winding  of  the  cut-out  is 
connected  across  the  dynamo  brushes.  This  is  also  called  the  voltage  coil. 
The  series  or  current  coil  assists  in  holding  the  contacts  firmly  together. 

Lubrication. — The  bearings  should  receive  oil  every  week  or  every  200 
miles.  Use  a  high  grade  motor  oil.  Place  from  eight  to  ten  drops  in  each 
of  the  oiling  places.  Be  very  certain  to  replace  the  oil  covers  in  order  to 
exclude  all  foreign  substances.  Do  not  assume  that  the  oil  is  reaching  the 
bearings,  but  make  absolutely  certain.     Overflow  of  oil  at  the  oiling  places  is 


Starting  Motors  and  Generators 


453 


5       2 


/^S^Oi/0 


no  indication  that  the  bearing  has  oil.     At  times  oil  passages  to  bearings  will 
clog. 

Speed  and   Output. — The    dynamos   are    designed   to   be    driven   at   engine 
speed  or  one  and  one-half  times  engine  speed.     The  first  delivers  its  full  out- 


454 


Automotive  Trade  Training 


Fig.  534.     Gray  &  Davis  Brush   Rigging— Third  Brush  Type. 

put  at  500  R.  P.  M.  The  one  and  one-half  engine  speed  machine  delivers  full 
output  at  650  R.  P.  M.  In  either  case  this  corresponds  to  a  car  speed  of  from 
ten  to  twelve  miles  per  hour.  If  the  car  speed  is  less  than  this,  the  output  is 
also  less.  At  speeds  above  this  the  maximum  output  is  maintained.  If  no 
current  is  used  for  lighting,  all  the  generated  current  excepting  that  needed 
for  ignition  is  used  for  charging  the  battery  and  the  ammeter  will  show  prac- 
tically the  full  output,  as  flowing  to  the  battery.  When  the  lights  are  burning 
the  charging  current  is  reduced,  although  the  output  is  more  than  sufficient 
to  burn  all  of  the  lamps. 

Other  causes  which  will  result  in  a  falling  off  of  the  amount  of  the  charg- 
ing current  are  a  sulphated  battery,  or  one  in  which  the  battery  gravity  is  low. 


11     4     8      5     6     7. 

■  \  ■  \   \   V.^^^^ 

^     ^ 

^- 

1   Bflf^^j                         r'j35®^r? 

P 

r 

^. 

^^B^-nppi      B 

\ 

13 

wv 

•;,ji 

Fig.   535.     Cut-out   Housed   in   Dynamo,     Gray   and    Davis, 


Starting  Motors  and  Generators 


455 


This  is  due  to  the  increased  internal  resistance  when  a  battery  is  in  poor  con- 
dition. 

Operation. — To  determine  if  the  dynamo  is  functioning  properly,  the 
mechanic  should  observe  the  ammeter  carefully.  With  lights  ofif  start  the 
engine  running.  Increase  the  speed  very  gradually.  If  the  ammeter  begins  to 
register  at  a  speed  corresponding  to  seven  to  nine  M.  P.  H.,  it  indicates  that 
the  automatic  cut-out  is  cutting  in  (closing)  at  the  correct  time.     As  the  speed 


Fig.  536.     Gray  &  Davis  Cut-out— Used  on  Third  Brush  Dynamo. 

is  increased  the  ammeter  should  register  from  twelve  to  fifteen  amperes  at  a 
car  speed  of  thirteen  to  eighteen  miles  per  hour.  Above  eighteen  miles  per 
hour  and  at  high  speeds  the  ammeter  will  show  a  gradual  falling  off  of  the  out- 
put.    This  is  approximately  ten  amperes  at  the  higher  speeds. 

The  engine  speed  should  next  be  decreased  as  gradually  as  it  was  formerly 
increased  all  the  while  watching  the  ammeter.  If,  as  the  ammeter  shows  a 
discharge  of  0  to  2,  the  hand  suddenly  returns  to  0,  the  indication  is  that  the 
cut-out  is  opening  the  circuit  properly.     However,  if  the  ammeter  hand  indi- 


Fig.  537.     Gray  &  Davis  Internal  Wiring,  Third  Brush  Dynamo. 

Gates  a  decided  discharge,  or  should  fail  entirely  to  return  to  0,  the  indications 
are  at  least  a  sluggish  opening  of  the  points  and  possibly  burned  aud  stuck 
contact  points  in  the  cut-out. 

If  the  ammeter  fails  to  indicate  any  charge  when  the  engine  is  speeded 
up,  the  first  point  is  to  determine  whether  the  cut-out,  dynamo,  or  wiring  is 
at  fault.  The  wires  between  the  battery  and  dynamo  should  be  examined. 
The  battery  terminals  are  very  frequently  at  fault.  The  brushes  and  commu- 
tator should  be  examined  next.  The  brush  holders  are  equipped  with  stops 
which  prevent  the  brush  wearing  down  beyond  a  certain  point.  Refer  to  Job 
189  for  further  instructions.     Failing  to  have  eliminated  the  trouble,  the  next 


456  Automotive  Trade  Training 

step  is  to  connect  a  wire  from  the  negative  dynamo  brush  13  in  Fig.  537,  to 
dynamo  terminal  6.  With  the  engine  operating  at  a  13  M.  P.  H.  speed  the 
cut-out  is  out  of  the  circuit.  An  indication  of  charge  and  discharge  then 
appearing  on  the  ammeter  as  the  engine  is  operated  would  place  the  fault  with 
the  cut-out.  However,  if  the  ammeter  fails  to  register  the  fault  is  in  the 
generator.  Go  carefully  over  all  brushes,  terminals,  fuses,  and  wiring.  Failing 
to  correct  the  trouble,  the  machine  must  be  tested  with  the  Faultfinder  or  some 
similar  instrument  as  indicated  in  Jobs  174  to  188. 

The  car  must  not  be  operated  with  the  battery  removed  unless  proper 
precautions  are  taken.  In  this  case  the  method  recommended  is  to  raise  one 
of  the  brushes  from  the  commutator  and  tie  it  in  that  position.  This  prevents 
the  generator  building  up  an  excessive  output  and  voltage  with  the  attendant 
dangers  of  burned  and  damaged  parts. 

Adjusting  Third  Brush. — Fig.  534  shows  the  yoke  with  the  two  main 
brushes  13  and  14.  The  third  brush  is  indicated  by  12.  When  attempting 
to  adjust  the  third  brush  to  secure  an  increased  or  decreased  output  an  amme- 
ter must  be  in  line,  either  the  one  on  the  dash  or  a  portable  one.  The  battery 
should  be  fully  charged.  The  adjustment  is  secured  by  turning  pinion  11, 
which  is  provided  with  a  slot  for  a  screw  driver  blade.  This  is  shown  in  Fig. 
535  on  the  outside  of  the  housing.  A  very  slight  turn  will  affect  the  output 
very  materially.  Turning  to  the  left  will  increase  the  output,  and  to  the  right 
will  decrease  the  charging  rate.  The  speed  at  which  the  driver  operates  his 
car  has  much  to  do  with  the  output.  If  the  car  is  driven  regularly  at  high 
speeds  the  tapering  ofif  or  falling  ofif  due  to  the  armature  reaction  may  be 
partially  overcome  by  setting  the  third  brush  for  a  low  charging  rate  at  a  low 
engine  speed.  This  will  delay  the  armature  reaction  and  the  result  will  be 
that  the  maximum  charging  rate  will  come  at  a  relatively  higher  car  speed 
resulting  in  a  greater  output. 

The  internal  wiring  diagram  is  shown  in  Fig.  537. 

JOB  155.     GRAY  AND  DAVIS  STARTING  MOTOR  TWO  UNIT 

SYSTEM. 

The  starting  motor  is  the  link  between  the  battery  and  the  engine.  In 
cranking  the  engine  it  converts  the  electrical  energy  drawn  from  the  battery 
into    mechanical    energy. 

Electrically,  it  is  connected  to  the  battery  with  heavy  cables.  Mechan- 
ically, it  is  connected  to  the  engine  through  a  gear  reduction.  The  principal 
parts  are  shown  in  Fig.  539.  This  illustration  shows  the  automatic  pinion 
shift  type  (Bendix  Drive).  Mounted  on  the  armature  shaft  is  a  sleeve  having 
screw  threads,  with  stops  on  either  end  to  limit  the  travel  of  the  pinion.  The 
pinion  has  internal  threads  making  it  a  smooth  running  fit  on  a  threaded 
sleeve.  The  pinion  is  weighted  on  one  side.  This  sleeve  is  connected  to  the 
motor  shaft  proper  through  a  spring  attached  to  a  collar  pinned  to. the  motor 
shaft. 

Normally  the  pinion  is  in  a  demeshed  position.  When  the  starting  switch 
is  closed,  by  pressing  down  on  it,  the  armature  of  the  machine  immediately 
starts  rotating.  Since  the  threaded  sleeve  is  connected  to  it  through  the 
spring,  it  is  also  set  in  motion.  The  motor  pinion  being  weighted  on  one  side 
does  not  start  rotating  immediately,  but  moves  endwise.  This  endwise  motion 
causes  it  to  mesh  with  the  teeth  cut  on  the  flywheel.  When  the  limit  of  its 
travel  endwise  is  reached,  the  pinion  must  turn  with  the  sleeve  and  armature. 
The  spring  acts  as  a  cushion  while  cranking  against  compression.  It  also 
breaks  the  severity  of  the  shock  in  case  of  backfire. 

When  the  engine  begins  to  operate  under  its  own  power,  the  increased 
speed   of  the   fly   wheel   causes   the   engine   to   attempt   to   drive   the    starting 


Starting  Motors  and  Generators 


457 


CONNECTION  TO  ARM.  SHAFT 


CONNECTION  TO  SCREW 
SHAFT^ 
PINION 


STARTING 
SWITCH 


SCREW  SHAFT 


STOP 
COLLAR 


ARM. 
SHAFT 


FLY  WHEEL 


Fig.  538.     Gray  &  Davis  Starting  Motor  Application. 


FELT 


STOP/*- 
COLLAR 


BRUSH 
YOKE 


GROUND 
CONNECTION 


SCREW 
SHAFT 


ARMATURE       COMMUTATOR 


PINION  CAGE 

Fig.   539.     Gray   &  Davis  Motor  Parts.     Outboard   Automatic   Pinion   Shift   Type. 

motor.  This  results  in  the  pinion  being  thrown  out  of  mesh  since  no  power 
can  be  transmitted  backward  until  the  pinion  is  against  the  other  collar.  At 
this  point  it  is  out  of  mesh.  The  centrifugal  effect  of  the  weighted  side  of  the 
pinion  causes  the  pinion  to  be  maintained  out  of  mesh  until  the  armature  has 
come  to  a  stop.  It  is  needless  to  emphasize  the  necessity  of  removing  the  foot 
to  perrnit  the  switch  to  open  as  soon  as  the  engine  is  operating  under  its  own 
power. 

Lubrication. — The  starting  motor  must  be  oiled  regularly  every  two  weeks. 
Eight  to  ten  drops  of  light  motor  oil  should  be  placed  in  each  of  the  oil  recept- 


458 


Automotive  Trade  Training 


acles.     Sliding  surfaces  and  rods  must  be  oiled  frequently.     Use  kerosene  on 
the  threaded  motor  shaft  to  keep  it  clean. 

Failure  to  Start. — If  the  starting  motor  cranks  the  engine  when  the  start- 
ing switch  is  depressed  to  the  full  limit  of  its  travel,  but  the  engine  fails  to  fire 
and  run  under  its  own  power,  the  starting  pedal  must  be  released  after  ten 
to  fifteen  seconds.     The  cause  of  failure  may  be  any  of  the  following: 

Fuel  supply  exhausted. 
Ignition  switch  not  turned  on. 
Ignition  wires  not  firmly  connected. 
Spark  plugs   defective. 
Cylinders  need  priming. 
Cylinders  flooded  from  too  much  priming. 
Carburetor  out  of  adjustment. 
Poor  grade  of  fuel. 

Reasons    for    Cranking    Failures. — If    de- 
pressing  the   starting   pedal   fails   to   cause   the 
starting  motor  to  rotate  and  the  engine  .to  turn 
the   fault  may  be  any  of  the   following: 
Battery  weak  or  discharged. 
Loose  battery  terminals. 
Starting  switch   not   making  good   contact 
when    pedal    is    depressed    to    the    limit    of    its 
travel.       To     remedy     this     press     blades     out 
slightly.     Refer  to   Fig.  540. 

Crank  engine  by  hand  to  see  if  the  fault  is 
in  it. 
They    should    make    good    contact    and    swing 


Fig.  540.     Gray  &  Davis   Starting 
Switch. 


Examme    motor   brushes 
freely. 

See  that  commutator  is  clean. 

See  that  the  pinion  is  not  stuck  on  the  threaded  sleeve 


JOB    156.     HUDSON    DELCO    MOTOR    GENERATOR   SINGLE    UNIT. 

The  Delco  single  unit  used  on  the  Hudson  engine  is  typical  of  Delco 
equipment.  The  same  armature  serves  for  both  starting  and  generating. 
However,  the  windings  are  separate  and  the  commutator  on  the  rear  end 
is  used  only  for  the  generator  while  the  commutator  on  the  front  end  is  used 
only  for  the  motor  as  it  operates  in  starting  the  engine.  A  set  of  brushes, 
with  which  the  motor  end  is  equipped,  are  in  contact  with  the  commutator 
only  while  the  cranking  effort  actually  takes  place.  This  prevents  undue  wear 
on  them  while  the  machine  is  used  for  the  work  of  generating  and  recharging 
the  storage  battery.  The  car  is  not  equipped  with  the  usual  type  of  starting 
switch.  The  raising  and  lowering  of  the  brushes  is  the  equivalent  of  the  switch 
action  in   this   case. 

Cranking  Operation. — When  the  starting  pedal  is  depressed,  it  causes  the 
motor  clutch  to  engage  with  the  teeth  of  the  fly-wheel  and  with  the  motor 
pinion  gear.  Connected  to  the  pedal  mechanism  is  the  brush  controlling 
mechanism.  When  the  starting  pedal  is  depressed,  the  brushes  are  allowed  to 
come  into  contact  with  the  commutator.  This  then  permits  the  current  to 
flow  from  the  positive  terminal  of  the  storage  battery  to  the  series  winding 
of  the  motor,  to  the  upper  motor  brush,  through  the  armature  to  the  lower 
brush,  through  the  lower  brush  and  frame  of  the  car  to  the  negative  terminal 
of  the  battery.  It  is  seen  how  the  movement  of  the  starter  pedal  thus  con- 
nects the  motor  to  the  engine  and  at  the  same  time  closes  the  switch  which 
in  this  case  is  the  motor  brushes.  The  wiring  diagram,  Fig.  542,  shows  the 
motor  brushes  lifted.     The  cranking  circuit  may  be  traced  out  on  the  diagram. 


Starting  Motors  and  Generators 


459 


Fig.  541  shows  the  actual  wiring  necessary  to  connect  the  motor  to  the  battery. 
As  stated  previously  the  negative  brush  is  grounded  as  is  also  the  negative 
battery  terminal.  Fig.  543  shows  the  motor  commutator  and  the  brushes, 
together  with  their  springs  and  operating  pin. 

Operating  as  a  Generator. — When  the  ignition  switch  is  closed,  the  gener- 
ator will  start  motoring.  This  is  due  to  the  fact  that  no  automatic  cut-out 
is  employed,  and  the  action  of  closing  the  ignition  switch  closes  the  charg- 
ing circuit  as  well.     Since  the  pressure  of  the  battery  is  thus  admitted  to  the 


460 


Automotive  Trade  Training 


cc 
3(0E       StoC     ^Sju      «ta 


WVWVhH 


rl"l'lh-> 


charging  circuit,  current  is  caused  to  flow  to  the  generator  from  the  battery. 
This  flow  of  current  amounting  to  four  or  five  amperes  is  sufficient  to  cause 
the  generator  armature  to  rotate  at  a  slow  speed.  In  some  Delco  models  this 
is  evidenced  by  the  ratchet-like  noise  of  the  over-running  clutch. 


Starting  Motors  and  Generators  461 

The  purpose  of  the  design  which  incorporates  the  motoring  armature  is 
to  insure  the  starting  motor  pinion  engaging  properly  with  the  fly-wheel 
teeth  as  the  starting  pedal  is  depressed.  As  noted  previously,  the  same 
action  which  throws  the  gear  into  mesh  with  the  fly-wheel  also  applies  the 
starting  motor  brushes  to  the  commutator  of  the  starting  motor.  A  third 
operation  is  performed  by  this  same  operation,  and  that  is  opening  the  gener- 
ator switch. 

The  generator  switch  which  is  shown  in  the  wiring  diagram,  Fig.  542,  as 
well  as  in  the  illustrations  of  the  motor  generator,  Fig.  543  and  544,  serves  to 


1 

1 

jBBBSiwlBBfc, 

jg^^^^^^^^HHHIII^^^^^H^                      CONNECTS   TO 

^^^■■■jJI^^^^M^^^^^^^^SW^    ^^TERMiNAL             2) 

GENERATOR 

' J^^^H^^^^^B^^^Bh^  ' 

SWITCH       "~"~~-~-^ 

! 

H^^S^^9|^H||^^^^|^H^^^H&         >    CONNECTS  TO 
■MK^^^^^^H^^^HPH^^^^^H^^GENERATOR    BRUSH 

IIPPPR     MHTnR    . 

HI^^IH^^^sHHi 

BRUSH 

^SSSBS^SB^^K^k 

OIL    HOLE ""^ 

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MOTOR  — —         ' 

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COMMUTATOR 

^^^^^^^^Hl 

LOWER    MOTOR 

^^^^^■B 

BRUSH     — -__ 

|H^HKp 

f 

^ — -PIN    OPERATING    MOTOR    BRUSHES 

1 

fc 

W 

1 

Fig^.  543.     Hudson  Delco   Motor  Brushes  and   Commutator. 

connect  the  battery  to  the  generator  winding,  on  the  armature,  at  all  times, 
excepting  only  when  the  starting  pedal  is  depressed  and  the  engine  is  being 
cranked. 

After  the  engine  starts  operating  under  its  own  power,  the  generator 
switch  is  closed  as  the  pedal  is  released  and  current  flows  through  the  charg- 
ing circuit.  As  long  as  the  engine  continues  to  operate  above  a  speed  suffi- 
cient to  overcome  the  battery  voltage  the  current  will  flow  from  the  gener- 
ator to  the  battery.  When  the  car  speed  or  engine  speed  drops  down,  the 
current  will  reverse  in  the  charging  circuit  and  flow  from  the  battery.  To 
stop  the  flow  of  current  within  the  circuit,  it  is  necessary  to  open  the  igni- 
tion switch,  which  at  the  same  time  opens  the  shunt  winding  of  the  generator. 

Regulating  Generator  Output. — The  Hudson  Delco  equipment  is  con- 
trolled by  the  third  brush  method.  The  position  of  the  brush  on  the  com- 
mutator controls  the  output.  The  output  is  regulated  at  the  factory  and 
should  be  satisfactory  for  the  average  driving  conditions. 

If  it  should  become  necessary  to  increase  the  output,  first  remove  the 
cover  plate  over  the   third  brush.     The   next   step  is  to  loosen   the   two   set 


462 


Automotive  Trade  Training 


screws  in  the  arm  of  the  third  brush  and  move  the  brush  to  the  right  (look- 
ing at  the  front  end  of  the  generator).  A  small  movement  will  make  quite 
a  difference  in  the  charging  rate.  To  decrease  the  output  move  the  third 
brush  to  the  left.  Be  certain  to  set  up  the  screws  snug  and  tight,  to  prevent 
parts  coming  out  of  adjustment.  It  is  also  necessary  to  sand  in  the  brush 
in  its  new  position.     Refer  to  Job   189   for   instructions. 

At  nine  miles  per  hour  the  charging  rate  should  be  five  amperes,  at  twelve 


CONNECTS  TO 
TERMINAL  (No.  2) 


GENERATOR 
TERMINAL  (No.  2) 


CONNECTS  TO 
GENERATOR  BRUSH 


GENERATOR  SWITCH 


SHUNT  FIELD 
TERMINAL  (No.  4) 


MOTOR  PINION 


MOTOR  TERMINAL  (No.  1) 


J 


Fig.   544.     Hudson   Delco    Side  View   of  Generator. 

miles,  ten  amperes,  and  at  twenty-four  miles  the  maximum  is  reached  which 
is  seventeen  amperes,  after  which  point  the  output  drops  off  rather  rapidly 
until  at  42  miles  per  hour  the  output  has  dropped  back  to  eleven  amperes. 

The  operator  must  remember  that  with  this  system  the  drain  on  the 
battery  is  two-fold  if  the  ignition  switch  is  inadvertently  left  on,  since  the 
drain  is  both  to  the  ignition  and  the   generator. 


JOB  157.     MAXWELL  SIMMS  SYSTEM. 

This  system  is  a  twelve-volt  single  unit  type.  It  is  so  mounted  on  the 
Maxwell  engine  that  the  one  end  of  the  armature  shaft  may  be  used  for  driv- 
ing the  engine  through  the  starter  pinion  and  the  other  end  receive  the  power 
from  the  engine  which  drives  the  machine  as  a  generator.  This  arrangement 
is  possible  due  to  the  fact  that  the  generator  drive  is  one  of  belt  friction. 

The  generator  driving  shaft  is  connected  to  the  small  end  of  the  armature 
shaft  by  means  of  a  flexible  coupling.  The  forward  end  of  the  shaft  is 
equipped  with  a  pulley.  The  generator  is  driven  at  about  two  and  one-half 
times  engine  speed  by  the  fan  belt.  When  the  motor  generator  is  connected 
to  the  fly-wheel  pinion,  however,  the  generator'  speed  is  about  nine  times  the 
engine  speed.     As  this  connection  is  a  positive  one,  the  fan  belt  slips  on  the 


Starting  Motors  and  Generators 


463 


generator  pulley  during  the  time  that  the  motor  is  used  for  starting  or  crank- 
mg  the  engine.  In  this  manner  the  use  of  over-running  clutches,  or  ratchets, 
is    done    away    with. 

Starting  Conditions. — Refer  to  Wiring  Diagram  Fig.  547  for  the  numbers 
and  circuits  mentioned.  Under  starting  conditions  the  starting  switch  plunger 
is  moved  forward  and  completes  the  circuit  between  5  and  6.  The  same 
movement  connects  the  starter  pinion  or  meshes  it  with  the  fly-wheel  gear. 
This  is  not  shown  on  the  wiring  diagram.  The  path  of  the  current  is  then 
as  follows: 

Starting  at  the  storage  batter.y  from  terminal  8  the  current  flows  through 


Fig.  545.    Maxwell   Simms  Motor  Generator. 


connection  9  to  contact  6,  through  connector  10,  through  contact  5,  in  the 
starting  switch,  then  to  terminal  11  at  the  generator  through  the  positive 
brush  14  into  the  armature  to  the  negative  brush  15,  through  the  series  winding 
of  the  field  pole,  and  thence  to  the  frame  or  ground  of  car  to  terminal  13  and 
negative  pole  of  the  battery. 

Charging  Conditions. — After  the  current  has  flowed  from  the  battery  and 
through  the  circuit  indicated  above,  thus  starting  the  engine  to  running  under' 
its  own  power,  the  foot  pedal  is  released,  which  in  turn  demeshes  the  pinion 
and  opens  the  switch  leaving  it  in  the  position  shown  in  Fig.  547.     The  fan  belt 

drive  for  the  generator  now  becomes 
operative.  The  residual  magnetism  left 
in  the  field  poles  is  sufficient  to  start  the 
machine  generating.  Current  is  gener- 
ated between  the  two  main  brushes  14 
and  15.  Starting  from  the  third  brush 
13,  the  current  travels  through  the 
shunt  field  coils  to  the  frame  of  the 
motor,  through  the  series  field  coil,  and 
back  through  the  negative  brush  15. 
This  shunted  current  passing  through 
the  field  winding  produces  a  stronger 
magnetic  field  to  be  cut  by  the  armature 
winding,  and  consequently  permits  the 
voltage  or  pressure  to  be  built  up  and 
the  output  increased.  Starting  from 
Fifr.  54C.    Maxwell  Simms  Yoke,  terminal    11    the    current    flows    through 

Complete.  the  small   wire   to  termmal   16,   through 


464 

LEFT  HEAD  LAMP 


Automotive  Trade  Training 


RIGHT  HEAD  LAMP 


V 


OROUND \ ^         32    / .GROUND 


l^ljgHl|' 


GROUND     \    33 


'ii^.pqi 


GROUND 

I 


DISTRIBUTOR 


Starting  Motors  and  Generators  465 

the  voltage  coil  in  the  cut-out  17  to  the  ground.  This  causes  a  magnetic 
action  which  closes  the  contact  points,  whereupon  the  current  will  flow 
through  19,  20,  and  21,  through  the  coil  22,  through  terminal  23,  through  wire 
24  to  ammeter  terminal  26,  through  wire  27,  through  fuse  holder,  through 
terminal  9,  through  terminal  8,  through  terminals  7  and  12,  to  the  ground,  then 
through  the  series  winding  of  the  generator  field  and  back  to  the  negative 
terminal,  15,  of  the  machine. 

Generator  Output  Regulation. — Fig.  547  shows  three  cuts  marked  Slow 
Speed,  Medium  Speed  and  High  Speed.  The  relative  positions  of  the  two 
main  brushes  and  the  third  brush  are  shown.  The  lines  of  force  are  repre- 
sented by  twelve  lines  for  the  twelve  volts  output  of  the  system.  These  lines 
do  not  represent  the  winding,  but  the  lines  of  force  or  magnetism  of  the  field 
poles,  yoke  and  armature.  In  the  Slow 
Speed  it  will  be  noted  that  the  lines  of  force 
are  equally  divided  over  the  sttrface  of  the 
pole  shoe.  In  the  Medium  Speed  section  it 
will  be  noted  that  the  lines  are  distorted  in 
the  direction  of  armature  rotation.  This  is 
due  to  the  armature  reaction  as  explained 
in  the  early  part  of  the  chapter.  In  the  sec- 
tion marked  High  Speed  a  still  greater 
distortion  is  shown  which  is  representative 
of  the  actual  condition  in  the  field. 

If,  as  stated  above,  each  line  is  said  to 

represent  approximately  one  volt  and  there 

is  a  total  of  twelve  volts  per  pole,  and  the 

field  coil  is  connected  to  the  third  or  regu-  F*&-  548  Maxwell  Simms  Brush- 
,     .         ,         ,  ,     ,.  ,  ,         ^  Holder,  Complete, 

latmg  brush  one-half  way  between   the  two 

main  brushes,  the  student  will  see  that  the  resultant  distortion  of  the  increase 
of  speed  causes  fewer  lines  of  force  to  be  cut,  and  decreases  the  amount  of 
current  flowing  through  the  field  as  indicated. 

Since  the  current  output  is  dependent  on  the  three  factors,  armature  speed, 
armature  winding,  and  field,  it  is  evident  that  the  increase  of  speed  is  counter- 
acted by  the  decrease  of  the  lines  of  force  being  cut,  as  the  distorted  field 
insures.  Consequently  the  regulation  is  inherent.  The  shunt  field  is  wound 
for  seven  and  one-half  volts,  while  the  armature  output  is  approximately 
fifteen  and  one-half  volts  when  the  third  brush  is  properly  located  and  the 
armature  running  at  approximately  1500  R.  P.  M. 

JOB  158.     REMY  OLDSMOBILE. 

As  in  the  case  of  the  Remy  Ignition,  the  Remy  starting  and  lighting 
equipment  is  built  for  a  large  number  of  car  manufacturers.  The  Oldsmobile 
is  given  here  as  representative  of  the  Remy  line. 

Thermostat  Control. — The  student  no  doubt  understands  by  this  time  that 
the  thermostat  control  is  a  device  of  whatever  nature  which  is  so  arranged  to 
control  some  other  feature  of  equipment  because  of  certain  action  within  itself, 
due  to  heat.  In  the  chapter  on  Cooling  Systems  the  effect  of  heat  on  the 
thermostat  controlling  the  water  circulation  was  explained.  In  this  case  the 
heat  is  produced  by  running  a  current  of  electricity  through  a  bit  of  resistance 
wire  wound  on  a  metal  blade.  This  blade  is  made  up  of  two  metals,  one  with 
a  great  amount  of  expansion  when  heated,  the  other  one  not  subject  to  much 
expansion.  The  result  is  that,  when  the  current  flows  through  the  resistance 
wire  around  the  blade,  they  are  heated.  When  heated  beyond  a  certain  point 
the  blade,  owing  to  the  nature  of  its  construction,  will  curve,  thereby  throwing 


466 


Automotive  Trade  Training 


the  points  apart  and  inserting  another  resistance  unit  into   the   circuit  which 
will  cut  down  the  output  of  the  generator. 

In  the  Remy  this  device  is  used  in  connection  with  the  third  brush  control 
to  regulate  the  output  of  the  generator.     It  is  natural  that  more  current  would 


Fig.  549.     Remy  Oldsmobile  Generator  with  Ignition  Coil  and  Relay  mounted  on  it. 

be  required  in  the  cold  winter  months  to  open  the  thermostat  than  in  the 
warm  summer  months.  This  is  an  especially  desirable  feature  since  the 
demand  for  current  both  for  starting  and  lighting  is  much  greater  in  the 
winter  than  in  the  summer.  This  device  then  helps  to  insure  a  higher 
charging  rate  in  the  winter  to  compensate  for  the  heavy  demands  on  the 
battery.  The  device  is  entirely  automatic  and  requires  no  attention.  In  case 
of  serious  damage  to  it  a  new  unit  should  be  installed. 

Third  -Brush  Control. — The  output  of  the  generator  is  high  and  the 
thermostat  is  depended  on  to  prevent  overcharging.  However,  if  the  battery 
shows  signs  of  being  continuously  overcharged,  the  output  may  be  reduced  by 
means  of  the  third  brush  screw.  This  is  found  on  the  commutator  end  of  the 
generator  and  a  slight  turn  to  the  left  will  correct  the  trouble.  Likewise 
turning  to  the  right  will  increase  the  output.  This  should  never  exceed  twenty 
amperes,     Where  the  output  is  too  low,  look  for  brush  or  commutator  trouble. 


Fig.  550.     Remy   Oldsmobile  Starting  Motor. 


Starting  Motors  and  Generators 


467 


TO  CCNERATOR   FIELD 

fXl rf^ 


TO   SENERATOR   FIEL 


yvAAA/W"     ^ 


Fig,  551.     Remy  Oldsmobile  Thermostat. 

Relay. — This  Is  the  automatic  cut-out  previously  described.  The  Remy 
relay  shown  in  Fig.  553  consists  of  the  contact  points,  a  movable  arm  with  a 
spring  hinge,  and  a  simple  electro  magnet.  The  spring  holds  the  contacts 
apart  when  the  engine  comes  to  rest.     When  the  generator  is  being  driven  at 

THERMOSTAT 


3RD  BRUSH 


BRUSH  RIGGING  INSIDE 

Fig.  552.    Remy  Oldsmobile  Brush  Rigginfr  with    Thermostatic    Control    mounted 

on  the  inside. 

a  speed  sufficient  to  develop  a  voltage  equal  to  that  of  the  battery,  the  shunt  coil 
on  the  relay,  sometimes  called  the  voltage  coil,  is  energized  and  the  arm  bearing 
the  one  contact  is  pulled  down  to  the  other,  thus  closing  the  circuit  through 
MOVABLE  ARM 

CONTACT 
POINTS  

ELECTRO 
MAGNETS 


Fig.  553.     Remy  Relay. 


468 


Automotive  Trade  Training 


which  the  current  must  flow  to  reach  the  battery.  The  relay  is  provided  with  a 
series  coil,  through  which  the  current  flowing  to  the  battery  must  pass.  This 
insures  the  contact  points  being  held  firmly  together. 


Starting  Motors  and  Grxerators 


469 


Fig:.  555.     Studebaker  Wagrner  Generator. 


h'ig.  55t).     \v'aguer  Relay  Cutout. 


470 


Automotive  Trade  Training 


Care  of  Contact  Points  (Relay). — If  the  points  become  worn  or  dirty,  Or 
show  a  tendency  to  stick,  they  may  be  placed  in  good  condition  by  passing 
through  them  a  piece  of  No.  00  sandpaper.  Blow  out  all  dust  to  allow  a  clean, 
flat  contact.  Use  care  not  to  spring  the  arm,  or  to  change  the  opening  or  the 
spring  tension.  The  spring  tension  is  correct  unless  there  are  some  unusual 
circumstances  attending.  The  clearance  of  the  contacts  when  open  is  from 
.015"  to  .020". 

Starting  Motor. — This  is  a  four  pole  series  wound  machine.  A  Bendix 
drive  is  used. 

When  the  starting  switch  is  closed,  the  motor  starts  revolving  at  high 
speed.  The  pinion  gear,  by  reason  of  its  inertia,  tends  to  lag  behind  the 
rotation  of  the  shaft,  thus  being  thrown  into  mesh  with  the  teeth  cut  on  the 
fly-wheel.  As  soon  as  the  engine  starts  operating  under  its  own  power,  the 
pinion  is  driven  faster  than-  the  armature  and  threaded  shaft,  and  is  thus 
thrown  out  of  mesh  with  the  fly-wheel  teeth. 

This  arrangement  permits  of  a  large  starting  torque,  since  the  armature 
is  running  at  a  high  rate  of  speed  when  the  load  comes  onto  it. 


JOB  159.     WAGNER  GENERATOR. 

A  unique  feature  of  the  Wagner  Generator  in  its  application  to  the 
Studebaker  power  plant  is  the  fact  that  the  instrument  is  so  designed,  built, 
and  attached  as  to  operate  in  a  vertical  position.  The  Wagner  Company 
manufactures  generators  which  are  driven  in  the  more  common  horizontal 
position.     Fig.  555  illustrates  the  Studebaker  generator. 

This  instrument  is  built  along  the  usual  third  brush  regulation  lines.  One 
unique  feature  about  the  third  brush  arrangement  is  that  the  adjustment  is 
made  at  the  factory  and  then  sealed.  The  factory  guarantee  is  made  void  if 
this   seal   is    broken    by    anyone    other    than    a    Wagner    representative    in    the 


rd 


0-1 


ItORN  PUSH  BUTTON  ^-».(^ 


IGN.   AND  LIGHTING  SWITCH  r-STARTlNG    MOTOR 

■  in* 


STARTER   SWITCH. 


Fig.  557.     studebaker  Wiring  Diagram. 


Wagner  factory,  or  an  accredited  Wagner  service  branch.  This  emphasizes 
the  fact  that  a  properly  designed  generator  requires  very  little  adjustment  of 
output  if  attendant  equipment  is  maintained  and  used  properly. 

Generator  Care. — See  that  the  two  oil  holes  receive  a  few  drops  of  the 
best  oil  each  1000  miles  of  service.  Wipe  the  commutator  clean.  It  is  not 
usually  necessary  to  sand  in  the  brushes,  or  sand  down  the  commutator  for 


Starting  Motors  and  Generators 


471 


several  seasons'  service,  but  if  the  work  must  be  done,  follow  the  directions 
given  in  Jobs  189  and  190. 

Relay  Cutout. — This  works  automatically  to  cut  in  the  battery  at  approx- 
imately ten  miles  per  hour,  and  the  generator  will  give  the  maximum  output 
from  seventeen  to  nineteen  miles  per  hour. 

Wiring  Diagram. — Fig.  557  shows  the  Wagner  Studebaker  wiring  diagram. 
The  feature  in  this  diagram  of  special  interest  is  the  junction  box  where  all 
wires  are  brought  together  for  proper  connection  and  fuse  protection. 


JOB  160.     INSTRUCTIONS  FOR  THE  USE  OF  WESTON  MODEL  441 

FAULT  FINDER  FOR  TESTING  AUTOMOBILE  ELECTRIC 

STARTING,  LIGHTING  AND  IGNITION  SYSTEMS. 

Description  of  the  Instrument. — The  Weston  Model  441  Fault  Finder, 
illustrated  in  Fig.  558,  consists  of  an  ammeter  and  a  voltmeter  mounted  in  a 
convenient  case. 

Connections  to  the  instruments  are  made  by  means  of  cables  having  clips 

at  one  end  and  plugs  with  handles  at  the 
other  end.  The  plugs  are  pushed  in  posi- 
tion through  the  holes  in  the  marking  plate 
through  especially  constructed  contact 
clamps. 

The  Ammeter. — The  ammeter  is  self- 
contained,  having  a  range  of  30  amperes. 
The  scale  is  provided  with  the  zero  at  the 
center.  There  are  fifteen  divisions  each 
side  of  zero.  The  value  of  each  division  is 
two  amperes. 

The  ammeter  is  protected  against  in- 
jury by  burn-out  by  the  enclosed  glass  fuse 
mounted  on  top  of  the  instrument  case  be- 
tween the  two  instruments.  This  fuse  is  a 
standard    30-ampere    automobile    fuse. 

The  ammeter  must  always  be  con- 
nected in  circuit  so  that  the  full  current  of  the  circuit  under  test  will  pass 
through  it.  To  make  this  connection,  the  circuit  is  opened  at  some  convenient 
point  and  the  test  clips  are  attached  to  the  two  ends  of  the  break  just  made. 

To  trace  the  direction  of  the  current  flow  in  a  circuit  by  means  of  the 
ammeter,  it  is  only  necessary  to  remember  that  the  pointer  deflects  to  the 
right  of  the  zero  mark  when  the  current  enters  the  instrument  through  the 
contact  marked  +,  and  to  the  left  of  the  zero  mark  when  the  current  enters 
through  the  contact  marked  30. 


Fife'.  558.     Model  441  Fault  Finder. 


0^  VOLTS  \0/  AWEReI  \<^ 

LO     O     0(0     O) 


Fig'.   559.     Marking   Plate   for  Model  441   Garage   Testing   Instrument. 


The  Voltmeter. — The  voltmeter  is  a  double  range  instrument.  The  ranges 
are  0.2-0-3  volts  and  2-0-30  volts.  The  scale  has  30  divisions  above  zero  and 
two  divisions  below  zero.  Each  division  on  the  30-volt  range  has  a  value  of 
one  volt,  and  on  the  three-volt  range  0.1  volt. 

The  voltmeter  should  always  be  connected  over  that  part  of  the  circuit 


472 


Automotive  Trade  Training 


Fig.  560. 

across  which  the  voltage  is  to  be  determined.  When  using  the  voltmeter, 
connect  the  plug  which  is  in  the  (+)  hole  of  the  plate  on  the  side  marked  volts 
to  the  positive  (+)  wire  of  the  circuit,  and  the  other  plug  to  the  negative  ( — ) 
wire,  placing  the  plug  in  either  the  hole  marked  30  or  3,  according  to  the  range 
to  be  used. 

When  connected  as  just  explained,  the  pointer  will  move  to  the  right  of 
the  zero  if  the  polarity  of  the  circuit  is  correct. 

JOB  161. 

When  the  Starting  Motor  does  not  Operate. — To  determine  the  qause, 
proceed  as  follows:  Carefully  examine  all  connections  at  the  starting  switch 
and  at  the  motor.  Also  be  certain  that  the  brushes  of  the  starting  motor  are 
making  good  contact  on  the  commutator,  and  that  the  commutator  is  clean. 

Examine  contact  surfaces  of  the  starting  switch  to  be  sure  they  are  clean 
and  making  good  contact. 

Having  eliminated  possible  causes  of  trouble,  connect  the  30-volt  range 
of  the  voltmeter  across  the  battery  terminal  as  illustrated  in  Fig.  560.  Note 
the  reading. 

Case  A. — Close  the  starting  switch.  Again  note  the  reading.  If  it  is  the 
same  as  when  the  switch  is  open,  there  is  an  open  circuit  either  in  the  starting 
switch.  Job  162,  the  motor  field.  Job  163,  or  the  motor  armature.  Job  164. 

Case  B. — If  on  closing  the  starting  switch  a  small  decrease  in  the  reading 
results,  there  is  a  high  resistance  somewhere  in  the  circuit,  which  was  not 
located  by  the  preliminary  visual  inspection.  This  may  exist  in  the  battery 
terminals.  Job  166,  in  the  motor  field.  Job  163,  in  the  motor  armature,  Job  164. 
or  in  the  starting  switch.  Job  162. 

Case  C. — If,  on  closing  the  starting  switch,  a  large  decrease  in  the  reading 
results,  the  battery  may  be  exhausted,  a  short  circuit  may  exist  in  the  starting 
motor  field,  Job  168,  or  in  the  motor  armature,  Job  170,  or  in  the  wiring.  Job 
169. 

Case  D. — If  the  reading  on  the  voltmeter,  when  the  starting  switch  is 
open,  is  very  much  below  the  normal  voltage  of  the  battery,  one  or  more  cells 
of  the  battery  may  be  exhausted  or  defective,  or  a  short  circuit  may  exist  in 
the  wiring  between  the  battery  and  the  starting  switch.     (Job  169). 


Starting  Motors  and  Generators 


473 


JOB  162. 

Open  Circuit  or  High  Resistance  in  Starting  Switch. — Connect  the  30-volt 
range  of  the  voltmeter  to  the  terminals  of  the  starting  switch,  Figure  561.  If 
the  rest  of  the  circuit  is  in  good  condition  the  voltmeter  will  indicate  the 
battery  voltage;  if  it  does  not,  trouble  exists  in  some  other  part  of  the 
apparatus.     Close  the  starting  switch.     An  open  circuit  will  be  designated  by 


BATT£J?Y 


5rA/?T/N6  5W/TCH 


Fig.   561. 

no  change  in  the  reading.  A  small  change  in  the  reading  will  indicate  a  high 
resistance.  In  either  case,  the  contacts  of  the  starting  switch  and  all  connec- 
tions in  it,  or  to  it,  should  be  carefully  examined.  Contacts  should  be  cleaned 
or  repaired  if  found  to  be  poor.  If  the  switch  is  in  good  condition  the 
indication  will  drop  to  zero  o|;i  closing  it. 

JOB  163. 

Open  Circuit  or  High  Resistance  in  Motor  Field.^ — Connect  the  30-volt 
range  of  the  voltmeter  to  the  ends  of  the  field  coils  as  shown  in  Fig.  562. 
Close  the  starting  switch. 

An  open  circuit  in  the  field  coil  will  be  indicated  by  the  reading  of  the 
instrument  being  equal  to  the  battery  voltage.  Try  all  sections  of  the  field. 
A  good  field  will  be  indicated  if  the  instrument  reading  is  zero  or  nearly  zero. 
A  reading  which  is  somewhat  lower  than  the  battery  voltage  and  not  near  to 
zero  indicates  a  field  of  high  resistance.  Look  for  loose  connections  between 
sections  of  the  field  if  high  resistance  is  indicated. 


JOB  164. 

Open  Circuit  or  High  Resistance  in  Motor  Armature. — Connect  the  30-volt 

range  of  the  voltmeter  to  the  armature  terminals  as  shown  in  Fig.  563.  Close 
the  starting  switch.  If  the  voltmeter  shows  a  reading  equal  to  the  voltage  of 
the  battery,  the  armature  is  open.  A  good  armature  will  be  denoted  by  a 
very  low  reading.  A  high  resistance  will  be  denoted  by  a  reading  somewhat 
lower  than  the  battery  voltage  but  considerably  above  zero. 

An  open  circuit  may  be  in  the  brush  leads.     These   should  be   carefully 


474 


Automotive  Trade  Training 

BATTERY  5TARTl/\/G  5WJTCH 


Fig.    5G2. 

examined.  Other  causes  may  be  burned-out  coils  or  broken  wires  in  the  coils, 
or  brushes  not  bearing  on  the  commutator  because  the  spring  tension  is  poor; 
worn  out  brushes;  brushes  stuck  in  the  holders;  poorly  fitted  brushes;  high 
mica;  low  segments;  loose  or  poorly  soldered  connections. 

If  the  open  circuit  is  found  to  be  in'  the  armature,  the  same  should  be 
disconnected  from  the  field  and  one  cell  of  a  storage  battery  in  series  with  a 
lamp  bulb  connected  to  the  brushes  as  in  Fig.  564.  Connect  the  three- 
volt  range  across  the  brushes  and  note  the  reading.  If  it  is  equal  to  the  battery 
voltage  there  is  an  open  circuit  in  both  halves  of  the  armature.  If  it  is  less 
than  the  battery  voltage,  connect  one  of  the  test  cables  to  a  segment  lying 
under  a  brush  and  the  other  cable  to  the  adjacent  segment  as  shown  in  Fig.  564. 
Move  the  lead  on  around  the  commutator  one  segment  at  a  time,  and  if  the 
deflection  gradually  increases  to  approximately  the  value  obtained  across  the 
brushes,   the   half   of   the    armature   tested   does   not   contain   an   open    circuit. 


BATT£-RY 


STARTINS  SWITCH 


Fig.    563. 


Starting  Motors  and  Generators 


475 


20CAN0LE  POW£^ 
Head  L/G*^r  Bulb 


Fig.  564. 

If  a  segment  is  reached  on  which  the  deflection  suddenly  increases  to  approxi- 
mately the  value  obtained  across  the  brushes  an  open  circuit  exists  in  one 
or  more  of  the  coils  included  between  the  test  leads.  The  other  half  of  the 
armature  can  be  tested  in  the  same  manner.  In  order  to  test  the  coils  lying 
under  the  brushes  the  armature  should  be  rotated  slightly  and  the  test 
repeated. 

High  resistance  in  the  armature  circuit  may  be  due  to  broken  coil  wires 
which  are  lightly  touching  at  the  break,  poorly  soldered  connections  at  the 
commutator  bars,  poor  bearing  brushes,  and  dirty  commutator. 

JOB  165. 

High  Resistance  in  Ground  Connection. — Connect  the  30-volt  range  of  the 
voltmeter    to    the    terminal    of    the    battery    which    is    grounded    (usually    the 


BATTERY 


3TAieTlNG  5WITCH 


Pig.  565. 


476 


Automotive  Trade  Training 


negative  is  grounded),  and  the  frame  of  the  car.  When  doing  this  be  sure  that 
all  paint  or  other  insulating  substances  are  removed  and  that  connection  is 
made  to  the  metal.  Upon  closing  the  starting  switch  no  indication  will  be 
obtained  if  the  ground  connection  of  the  car  is  good.  If  it  is  poor,  a 
deflection  will  be  obtained.  To  remedy  this  condition  remove  the  ground 
connections  between  the  battery  and  the  frame  of  the  car.  Clean  the 
connection  lead  and  thfe  frame  where  the  connection  is  made.  Give  the 
cleaned  surfaces  a  coating  of  white  lead  and  make  the  connection  again,  being 
certain  that  it  is  tight.     Refer  to  Fig.  565. 

JOB  166. 

High  Resistance  in  Battery  Terminal. — This  may  occur  because  the  joint 
between  the  link  connecting  two  cells  and  the  terminal  connected  to  a  set  of 
plates  are  poor  or  loose. 

Connect  the  30-volt  range  of  the  voltmeter  as  shown  in  Fig.  566.  Close 
the  starting  switch.  No  indication  will  be  obtained 'if  the  joint  is  good,  but 
if  the  joint  is  defective  there  will  be  an  indication.  Try  all  joints  in  this 
manner.        '• 


s^rrfjey 


5TA/er/N6  SWITCH 


Fig.   566. 


JOB  167. 

Short  Circuit  in  Motor. — If,  when  the  instrument  is  connected  as  in  Fig. 
567,  an  indication  is  obtained  which  is  much  less  than  the  battery  voltage,  there 
is  a  short  circuit  in  the  motor;  or  if  the  car  has  a  grounded  system  there  may 
be  a  ground  in  some  part  which  should  be  insulated.  When  these  conditions 
are  indicated,  the  field  should  be  disconnected  from  the  armature  and  the 
following  test  made: 

Connect  a  dry  cell  and  either  the  Weston  6-10  Register  or  a  six-volt 
twenty-candle-power  headlight  bulb  in  series  with  the  field  coils.  Connect  the 
three-volt  range  of  the  voltmeter  across  one  of  the  field  sections.  Note  the 
reading.  If  zero,  the  field  section  is  probably  short  circuited.  Repeat  on  the 
other  sections.     Fig.  567. 

Note. — To  secure  the  best  results  from  this  test  an  instrument  having  a 
range  of  about  100-milli-volts  should  be  used.     The  Weston  Model  280  Garage 


Starting  Motors  and  Generators 


477 


6  ]/.  20CP  LAMP 


nAA/WW^ — M 


Fig.  567. 

Type  Volt-Ammeter  is  particularly  adaptable  for  this  purpose.     Refer  to  Fig. 
578. 

If  the  field  is  found  to  be  in  good  condition  the  armature  should  be  tested 
for  short  circuited  coils.  This  cannot  be  done  with  the  model  441  Fault  Finder. 
The  test  described  is  as  made  with  the  model  280  Garage  type  Volt-Ammeter. 


Fig.   568. 

Connect  as  shown  in  Fig.  568.  Using  the  100-milli-volt  range,  measure 
between  adjacent  segments  of  the  commutator.  A  short  circuited  coil  will  be 
indicated  when  the  instrument  reading  is  zero  or  very  near  to  zero  as  compared 
to  the  readings  on  good  coils. 

The  contact  at  the  segments  must  be  good,  otherwise  the  results  will  not 
be  reliable. 

JOB  168. 

Short  Circuited  Wiring  to  Starting  Motor. — If  the  system  is  a  two-wire, 
it  may  be  possible  for  the  insulation  to  become  rubbed  and  a  short  circuit  to 
result.     To  test  for  this,  disconnect  the  wires  from  the  starting  motor,  but  be 


478 


Automotive  Trade  Training 


careful  not  to  have  the  ends  touch  any  metal  parts  of  the  car.  Measure  the 
battery  voltage  with  the  starting  switch  open,  using  the  30-volt  range  of  the 
instrument.  Connect  the  instrument  cables  to  the  wires  which  have  been 
removed  from  the  motor  terminals.  Close  the  starting  switch.  A  reading 
equal  to  the  battery  voltage  shows  the  wires  are  good.  Zero  reading,  or  a  very 
small  reading,  indicates  a  short  circuit. 

Note. — On  one-wire  grounded  systems  a  ground  on  the  one  wire  acts  the 
same  as  a  short  circuit.     See  under  wiring  test,  Job  173. 


aArreer 


3TA^TWG5W/TCH 


Fig.   569. 

JOB  169.  V 

Open  Circuit  in  Wiring  to  Motor. — Connect  the  30-volt  range  to  the  motor 
terminals  as  shown  in  Fig.  569.  If  there  is  an  open  circuit  in  the  wiring  there 
will  be  no  indication  on  the  voltmeter  when  the  starting  switch  is  closed. 


COMMUTATOe 


Fig.   570. 


Starting  Motors  and  Generators  479 

JOB  170. 

Ground  in  the  Motor  Armature.— Remove  the  brushes  from  the  commu- 
tator and  disconnect  the  field.  Use  a  six-volt  battery  and  a  thirty-volt  range 
of  the  voltmeter. 

Fig.  570  shows  the  connection  to  be  made  at  the  commutator  and  at  the 
armature  shaft.  Any  indication  on  the  voltmeter  denotes  a  ground.  For  the 
armature  to  be  good  the  reading  must  be  zero. 

Grounded  armatures  are  usually  caused  by  damaged  insulation  of  the 
armature  coils. 

In  armatures  having  double  v^indings.  each  of  which  is  brought  out  to  a 
separate  commutator,  each  winding  should  be  tested  for  grounds  and  then  ihe 
connection  made  between  the  two  armatures  to  determine  if  the  insulation 
between  them  is  defective.     A  reading  indicates  defective  insulation. 

JOB  171. 

Ground  in  the  Motor  Field. — Disconnect  the  field  so  that  its  ends  may  be 
free  and  take  care  that  they  are  not  in  contact  with  any  metal  of  the  car.  Use 
the  battery  and  voltmeter  as  in  Job  170,  making  connection  to  an  end  of  the 
field  and  the  metal  frame  of  the  generator  or  motor.  An  indication  on  the 
voltmeter  shows  a  grounded  field.     Zero  reading  shows  a  good  field. 

On  single  unit  systems  the  generator  and  motor  fields  are  wound  on  the 
same  frame.  Test  each  field  separately  for  ground  to  the  frame,  then  attach 
the  test  leads  to  the  two  fields  to  see  if  their  insulation  is  defective.  A  reading 
indicates  defective  insulation. 

JOB  172. 

Grounded  Brush  Holders. — On  two-wire  circuits  all  brush  holders  are 
insulated  from  the  metal  parts  of  the  motor  or  generator.  In  the  grounded 
return  systems  one  of  the  holders  is  in  metallic  connection  with  the  frame  of 
the  motor  or  generator. 

Only  such  brush  holders  need  to  be  tested  for  ground  as  are  intended  to 
be  insulated.     Usually  these  are  very  readily  detected  by  visual  inspection. 

In  order  to  make  the  ground  test  on  brush  holders  it  is  advisable  to  either 
remove  the  brushes  or  to  put  pieces  of  paper  under  them  to  insulate  them 
from  the  armature.  Then  with  the  voltmeter  and  battery  connected  as  in  Job 
170,  Fig.  570,  connect  the  test  leads  to  the  metal  of  the  brush  holder  and  the 
metal  frame  of  the  motor  or  generator.  If  the  insulation  is  good  the  reading 
will  be  zero.     Any  reading  other  than  zero  indicates  a  ground. 

JOB  173. 

Grounded  Wiring  to  Motor. — Disconnect  the  wires  from  any  apparatus 
they  may  be  attached  to.  Be  careful  that  the  ends  are  not  in  contact  with 
metal  parts  of  the  car.  Connect  the  voltmeter  and  a  battery  as  shown  in  Fig. 
570,  Job  170.  Connect  one  of  the  test  cables  to  the  end  of  the  suspected  wire 
and  the  other  test  cable  to  the  frame  of  the  car.  Zero  reading  means  good 
insulation.  Any  other  reading  denotes  defective  insulation.  On  two-wire 
circuits  test  each  wire. 

JOB  174. 

To  Determine  if  Generator  is  Generating. — Connect  the  30-volt  range  of 
the  instrument  to  the  terminals  of  the  generator  and  run  the  engine  at  its 
normal  sp'feed,  Fig.  571.  The  voltmeter  indication  should  build  up  to  about  seven 
volts  on  a  normal  six-volt  system  when  the  cut-out  relay  will  close  and  the 
circuit  through  the  battery  be  completed.     If  the  voltmeter  does  not  show  any 


480 


Automotive  Trade  Training 


cur  OUT  ^t LAY 


Fig.   571. 

indication  or  one  that  is  very  nearly  zero  the  field  regulator  is  not  working, 
Jobs  175  to  179,  the  armature  may  be  open  circuited,  Job  181,  the  field  may  be 
open  circuited,  Job  180,  or  either  may  be  short  circuited.  Jobs  182-183,  or 
grounded,  Job  184. 


curoun^ELAY 


CONTACTS 

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^STARTING  Motors  and  Generators 


481 


If  the  voltage  goes  much  above  seven  volts,  it  is  an  indication  that  the 
cut-out  relay  is  not  operating  properly. 

JOB  175. 

Defective  External  Field  Regulator. — With  the  instrument  connected  to 
the  30-volt  range  as  shown  in  Fig.  572,  place  a  short  circuiting  wire  around  the 
field  regulator  so  as  to  cut  it  out  of  the  circuit.  If  the  voltmeter  indication 
goes  up  to  the  proper  value  the  regulator  is  defective  and  should  be  repaired. 

JOB  176. 

Mercury  Tube  Regulator. — When  the  mercury  tube  type  of  regulator  is 
used  the  mercury  tube  and  plunger  should  be  short  circuited  when  making  this 
test. 

JOB  177. 

Series  Field  Regulator. — When  the  regulation  is  accomplished  by  a  series 
field  connected  to  produce  a  bucking  effect,  this  should  be  short  circuited  as 
shown  in  Fig.  573.  The  instrument  is  connected  to  the  30-volt  range.  If  the 
series  field  is  open,  upon  bridging  it  with  the  wire  the  voltage  will  immediately 
be  indicated. 

If  the  series  field  was  short  circuited  within  itself,  the  voltmeter  would 
show  an  indication  when  the  bridging  wire  was  removed.  The  indication 
would  increase  above  normal  with  increased  speed  of  the  engine. 

Caution. — If  the  motor  is  also  used  for  starting  purposes  be  sure  that  the 
bridge  wire  is  removed  before  trying  to  crank  the  engine  with  the  starter. 


cur  our ^a AY 


r^^rtA/WWW 


Fig.   573. 


482 


Automotive  Trade  Training 


JOB  178. 

Vibrating  Regulator. — When  the  regulator  is  of  the  vibrating  type,  bridge 
the  resistor  R  with  a  wire  as  in  Fig,  574,  and  connect  the  instrument  to  the 
30-volt  range. 

If  an  indication  of  about  normal  voltage  value  is  obtained  when  the  bridge 
wire  is  in  place,  either  the  resistor  R  is  open  circuited,  or  the  contact  blocks 
are  not  in  good  contact.     It  is  well  to  clean  the  contacts  carefully  and  make 


Fig.   574. 


CONTACTS  OPEN 


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1 

Fig.   575. 


Starting  Motors  and  Generators 


483 


the  test  with  the  bridge  wire  removed.  If  the  trouble  has  not  been  eliminated, 
try  the  resistor  for  open  circuit.  This  is  done  with  the  engine  stopped  and  a 
dry  cell  connected  in  series  with  the  three-volt  range  of  the  voltmeter  and  the 
resistor  as  in  Fig.  575.  The  contacts  should  be  held  open.  If  the  resistor  is 
not  open  circuited,  an  indication  will  be  obtained.  No  indication  means  an 
open  circuit.  If  the  resistor  were  short  circuited  a  voltage  reading  would  be 
obtained  when  making  test  Job  174,  but  the  voltage  would  increase  above 
normal  with  increase  in  engine  speed. 

JOB  179. 

Third  Brush  Regulation. — Failure  of  the  generator  with  -this  type  of 
regulation  may  be  caused  by  the  brush  not  bearing  on  the  commutator.  An 
incorrect  generated  voltage  ^would  be  due  to  the  third  brush  being  out  of  place. 
This  can  be  corrected  by  shifting  the  brush  until  the  proper  voltage  is 
obtained. 

JOB  180. 

Open  Circuit  in  the  Shunt  Field  of  Generator.— Do  not  run  the  engine. 
Disconnect  the  field  from  the  regulator  and  complete  the  circuit  through  the 
30-volt  range  of  the  voltmeter  as  shown  in  Fig.  576.  If  the  field  is  open 
circuited  no  indication  will  be  obtained. 


CuroUTjeELAY 


e 


Fig.   576. 


JOB  181. 

Open  Circuit  in  the  Armature  of  Generator. — Apply  the  latter  part  of  Job 
164  forr  locating  open  armature  coils. 

Examine  the  brushes  for  contact  and  the  connections  to  the  brush  holders. 


484 


Automotive  Trade  Training 


JOB  182. 

Shunt  Field  of  Generator  is  Short  Circuited. — Disconnect  the  field  from 
the  rest  of  the  machine;  connect  the  three-volt  range  of  the  voltmeter  across 
the  ends  of  the  field.  Then  connect  a  dry  cell  across  the  field.  If  a  short  of 
any  considerable  magnitude  exists  the  reading  of  the  instrument  will  be  zero 
or  very  nearly  zero.  If  the  field  is  not  short  circuited  the  indication  w^ill  be 
somewhat  near  that  for  the  voltage  of  the  cell.  It  will  be  a  little  lower  but 
probably  over  one  volt  for  a  good  dry  cell.     (Fig.  577.) 


Fig.   577. 
JOB  183. 

Short  Circuit  in  the  Armature  of  Generator. — This  test  is  best  performed 
with  the  Model  280  Garage  Type  Volt-Ammeter,  as  a  lOO-milli-volt  range  is 
needed.     The  method  to  pursue  is  as  follows:     Disconnect  the  armature  from 


Fig.   578.     Weston   Model  280   Garage   Type  Volt-Ammeter. 


Starting  Motors  and  Generators 


485 


the  rest  of  the  machine  and  try  for  open  circuited  coils  as  In  the  latter  part  of 
Job  164. 

Then  with  a  cell  or  battery  connected  in  series  with  a  suitable  resistor, 
such  as  the  Weston  Special  6-10,  manufactured  by  the  Ward  Leonard  Electric 
Co.,  of  Bronxville,  N.  Y.,  introduce  a  small  current  into  the  armature  through 
the  brushes.  Using  the  100-milli-volt  range  of  the  instrument,  test  between 
adjacent  segments  until  the  entire  armature  has  been  gone  over.  Short 
circuited  coils  will  be  denoted  by  a  zero  reading  or  by  a  reading  very  much 
less  than  that  obtained  on  a  coil  which  is  apparently  good.     (See  Fig,  568.) 

JOB  184. 

Grounded  Armature  or  Field,  or  Brush  Holders  on  Generator. — Proceed 
as  directed  under  Jobs  170,  171  and  172. 

JOB  185. 

Short  Circuit  on  Lines  Between  Generator  and  Battery. — Connect  the 
ammeter  as  shown  in  Fig.  579  on  the  generator  side  of  the  cut-out  relay. 
Run  the  engine  at  normal  speed  and  note  the  reading  of  the  ammeter. 

Then  change  the  position  of  the  ammeter  so  that  it  is  on  the  battery  side 
of  the  cut-out  relay  as  shown  in  Fig.  580.  The  reading  of  the  ammeter  should 
be  practically  the  same  as  before.  If  any  large  difference  exists  it  is  due  to 
a  short  circuit  in  the  lines  between  the  battery  and  the  generator. 

curour^aA'T 


Fig.   579. 
JOB  186. 

General  Tests  for  Relay  Trouble.— Connect  as  in  Job  174,  Fig.  571.  If 
the  relay  does  not  operate,  the  reading  of  the  voltmeter  will  go  above  seven 
volts  for  a  normal  six-volt  system.  This  may  be  due  to  an  open  circuit  in 
either  the  series  or  the  voltage  coils  of  the  relay. 


486 


Automotive  Trade  Training 
carourje£LAr 


COf^TACTS 


Fig.   580. 

JOB  187. 

Open  Circuit  in  the  Voltage  Coil  of  the  Relay. — Connect  the  441  instru- 
ment as  indicated  in  Fig.  581.     If  a  reading  is  obtained  the  coil  is  not  open 

curooreeiAY  \ 


Fig.  581. 


Starting  Motors  and  Generators 


487 


circuited.     If  no  indication  is  given,  move  the  test  lead  to  the  other  end  of 
the  winding.     If  a  reading  is  now  obtained  the  coil  is  open  circuited. 

JOB  188. 

Open  Circuit  in  the  Series  Coil  of  the  Relay. — Connect  the  instrument  as 
in  Fig.  582.  If  an  indication  is  obtained  the  battery  connections,  wiring  and 
generator  circuits  are  likely  in  good  condition. 

Next  move  the  test  lead  to  the  other  contact  point  so  as  to  include  the 
series  winding  of  the  relay  in  the  circuit  being  tested.  If  the  winding  is  in 
good  condition,  the  reading  should  be  approximately  equal  to  that  in  the 
first  test.     If  no  reading  is  obtained  the  coil  or  winding  is  open  circuited. 


CUrOUT££LAY 


Fig.  582. 

JOB  189.     FITTING  BRUSHES  AND  SANDING  COMMUTATOR. 

A  commutator  which  is  in  good  condition  shows  clean  and  bright  although 
it  may  be  of  a  purplish  color.  To  clean,  use  kerosene  on  a  rag  and  polish  with 
a  dry  cloth.  When  a  commutator  has  become  roughened  for  any  reason,  it 
should  be  sandpapered  with  either  0  or  00  sandpaper  or  cloth. ' 

SANDING  COMMUTATOR. 

1.  Cut  a  strip  of  sandpaper  the  width  of  the  commutator. 

2.  Pass  this  paper  through  under  the  brushes  with  the  generator  or  motor 
in  position  on  the  engine.  It  is  necessary  in  this  work  to  remove  only  the 
inspection  cover. 

3.  Keeping  the  ends  of  the  sandpaper  close  together  as  indicated  in  Fig. 
583,  work  the  paper  back  and  forth  until  the  commutator  is  bright  and  smooth. 
Turn  the  commutator  occasionally  as  the  work  progresses  in  order  that  all 
sides  may  receive  the  same  treatment. 

4.  Polish  the  commutator  with  a  rag  and  kerosene. 


488 


Automotive  Trade  Training 


SANDING  BRUSHES. 

1.  This  operation  is  similar  to  the  above  in  that  the  sandpaper  is  the 
width  of  the  commutator  and  the  machine  is  not  lifted  from  the  engine.  The 
sand  side  of  the  paper  however  is  placed  to  the  brushes  rather  than  against  the 
commutator. 

2.  Allow  the  normal  spring  pressure  to  be  exerted  on  the  brushes  as  the 
paper  is  worked  under  them. 

3.  Continue  the  sanding  until  the  brushes  are  a  perfect  fit  on  the  com- 
mutator. 

4.  This  remedy  will  properly  care  for  noisy  squeaky  brushes  as  well  as 
insure  the  proper  fitting  of  new  ones. 


BRUSH 


3ANO PAPER 
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Fig.  583.     Sanding  Commutator  and  Brushes. 


JOB  190.     UNDERCUTTING  MICA.    Turning  Down  Commutators. 

In  service  certain  commutators  will  wear  unevenly.  The  mica  insulation 
between  the  commutator  bars  is  harder  than  the  copper  bars  and  will  not  wear 
as  fast.  This  is  especially  true  in  the  case  of  generator  brushes  which,  as  a 
fule,  are  softer  than  the  motor  brushes.  When  this  condition  is  evident  the 
generator  will  not  work  properly,  due  to  the  fact  that  the  mica  holds  the 
brushes  away  from  the  commutator.  To  correct  this  trouble  proceed  as 
follows. 

A  high  or  low  bar  in  the  commutator  will  require  the  same  treatment  as 
tlic  high  mica, 

1.  Remove  the  generator  and  dismantle. 

2.  Place  the  commutator  in  the  lathe. 


Starting  Motors  and  Generators 


489 


3.  Set  the  lathe  tool  to  take  a  light  cut  over  the  surface  of  the 
commutator.  Remove  just  enough  metal  to  allow  the  commutator  to  come  out 
round. 

4.  Sand  the  commutator.     Run  the  lathe  at  a  high  speed. 

5.  Place  a  tool  in  the  lathe  which  is  so  ground  that  it  will  undercut  the 
mica.     This  tool  should  be  held  in  the  toolpost  and  cut  the  mica  as  the  carriage 


COMMUTATOR 


BRUSHETS 


1 1 

1 

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START/NC     G^OOVr    f/N    AffCA 
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SL.OTTING.      MICA     WITH 
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SEGMEIMTS 


SEdMEfi-rs, 


RIGHT      WAY 

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Fig.  584.    Turning  down  commutator  and  undercutting  Mica. 


is  moved  forward,  the  armature  being  secured  in  one  position.     The  proper 
depth  for  undercutting  the  mica  is  ih''. 

6.  If  the  operator  desires  to  do  this  work  by  hand  it  may  be  accomplished 
by  using  the  method  illustrated  in  Fig.  584.  A  hacksaw  blade  is  carefully 
ground  to  have  just  a  trifle  more  clearance  than  the  thickness  of  the  mica. 

7.  When  the  work  of  undercutting  has  been  finished  all  burrs  are  removed 
from  the  edges  of  the  commutator  bars.  The  commutator  then  receives  its 
final  polishing  before  assembling  the  generator. 

8.  It  is  best  to  refit  the  brushes  after  turning  down  the  commutator. 

9.  Keep  a  very  careful  watch  over  the  commutator  while  the  new  brushes 
are  wearing  to  a  good  seat.    This  will  be  within  200  miles'  service. 


CHAPTER  15 

WIRING  AND  LIGHTING 

As  intimated  in  a  previoue  chapter,  the  electrification  of  the  auto- 
mobile has  made  possible  its  most  rapid  development  and  refinement. 
Except  in  the  case  of  some  of  the  heavier  commercial  cars,  practically 
all  motor  vehicles  are  lighted  with  electricity.  The  generating  sys- 
tem together  with  the  storage  battery  form  a  very  necessary  part  of 
the  lighting  system.  Two  methods  of  wiring  the  lighting  system  are 
in  common  use.  These  are  known  as  the  single  wire  or  grounded 
return,  and  the  double  wire  or  insulated  return. 

Single  Wire  or  Grounded  System. — This  is  meeting  with  more 
and  more  favor.  It  makes  for  simplicity  in  the  construction  of 
sockets  and  related  parts  as  well  as  in  the  wiring.  The  single  wire 
is  run  from  the  source  of  current  to  the  light  bulb  socket,  and  is 
attached  to  it  by  means  of  a  screw.  Current  enters  from  the  wire, 
and  after  passing  through  the  filament  of  the  bulb  is  returned  to  the 
battery,  through  the  frame  of  the  car,  lamp  brackets  and  other 
metallic  parts.  The  student  will  be  able  to  pick  out  the  single  wire 
or  grounded  return  systems  illustrated  in  this  chapter  and  elsewhere 
quite  readily.  The  grounded  point  on  any  system  is  always  indicated 
in  the  conventional  manner. 

The  simplicity  of  the  single  wire  for  the  lighting  system  com- 
mends itself  to  the  average  mechanic  and  owner  as  it  is  far  easier 
to  trace  out  troubles  and  circuits  where  it  is  used.  In  cases  where 
it  is  used,  any  haphazard  grounding  of  a  single  wire  to  the  frame  is 
almost  certain  to  result  in  a  short  circuit,  since  the  frame  of  the  car 
might  be  likened  to  a  live  wire. 

Either  the  positive  or  the  negative  terminal  of  the  battery  may 
be  grounded. 

Double  Wire  or  Insulated  Return. — In  wiring  the  car  lamps  with 
this  system  twin  wire  is  used.  Twin  wire  has  the  two  stranded 
lighting  cables  laid  side  by  side  in  the  one  cable.  Each  cable  is 
covered  with  rubber  and  carefully  insulated  from  its  mate.  A  glance 
at  the  wiring  of  a  car  will  not  always  tell  whether  the  cable  used  to 
carry  the  lighting  current  is  the  single  or  double  wire  style.  Inspec- 
tion of  the  bulb  bases  will  indicate  immediately  which  system  is 
employed.  Where  the  two-wire  system  is  in  use  the  sockets  are 
equipped  with  two  screws  and  connections  for  attaching  the  lighting 
cables.  Due  to  the  small  size  of  the  fixtures,  the  mechanic  may 
experience  some  difficulty  in  making  a  workmanlike  job  of  attaching 
the  wires  to  the  socket.  A  ground  on  one  side  of  the  lighting  circuit 
running  to  any  one  lamp  does  not  mean  a  shorted  lamp  in  every  case. 

490 


Wiring  and  Lighting 


491 


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492 


Automotive  Trade  Training 


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Fig.  588.     Oakland  Wiring  Diagram. 


Wiring  and  Lighting  495 

It  may,  however,  lead  to  trouble  hard  to  locate,  especially  if  similar 
g-rounds  develop  elsewhere  in  the  lighting  or  ignition  circuits. 

Wiring. — Since  all  automobile  electric  systems  are  of  the  low 
voltage  type,  it  is  very  essential  that  all  wiring  be  of  sufficient  size 
to  carry  the  current  readily,  and  that  all  splices  in  the  wiring  or  cables 
be  properly  made  and  soldered.  A  connection  a  bit  loose  is  very 
likely  to  offer  so  much  resistance  that  current  will  not  flow.  Wher- 
ever splices  are  made  the  job  should  be  most  carefully  taped  to  pre- 
vent the  development  of  a  short  circuit. 

Where  wires  run  close  to  the  engine,  or  through  points  where 
the  liability  of  heat,  grease,  or  moisture  affecting  them  is  apparent, 
they  are  properly  protected  by  loom.  Loom  may  be  of  the  fabricated 
rubber  construction,  or  of  the  fiber  type,  or  as  in  the  case  of  more 
recent  usage,  of  the  flexible  metallic  type. 

Lighting  Switches. — There  are  many  types  of  lighting  switches 
on  the  market.  In  some  instances  the  lighting  switch  is  used  in  con- 
nection with  the  ignition  switch.  The  switch  may  have  a  separate 
push  button  for  each  light  or  set  of  lights,  or  it  may  be  so  constructed 
and  wired  to  give  only  those  combinations  for  which  there  is  most 
need.  These  combinations  are:  Headlights  full,  with  dash  and  tail 
lights  burning,  and  head  lights  dim,  with  tail  and  dash  lights  burn- 
ing. 

Head  Lights. — Head  lights  are  measured  by  the  diameter  of  the 
lens  or  the  distance  across  the  front  of  the  reflector.  They  will  vary 
from  8"  to  10".  A  bulb  of  from  15  to  30  candle  power  is  set  at  the 
point  of  focus  as  explained  in  a  later  paragraph,  and  in  this  way,  due 
to  the  highly  polished  surface  of  the  reflector,  is  made  to  throw  a 
beam  of  light  of  thousands  of  candle  power  onto  the  roadway.  Where 
no  side  lights  are  used  the  headlight  will  have  either  one  or  two 
bulbs.  If  two  bulbs  are  used  the  upper  one  is  a  small  one  of  low 
candle  power  and  is  used  for  city  driving  or  where  dimmers  are 
needed.  The  large  or  high  candle  power  bulbs  are  used  for  country 
driving,  or  where  a  strong  light  is  needed. 

Where  side  lights  are  used  they  take  the  place  of  the  small  bulbs 
in  the  headlight. 

Where  only  a  large  bulb  is  in  use  in  the  headlight  and  no  side 
lights  are  provided,  two  means  of  dimmiilg  are  used.  The  most 
common  of  these  is  to  have  the  switch  so  arranged  as  to  cut  in  a  bit 
of  resistance  wire  thus  reducing  the  amount  of  current  flowing  to  the 
headlight  bulbs.  The  other  method  is  to  so  wire  the  lights  and 
switch  as  to  throw  the  two  bulbs  in  series.  This  will  dim  them  quite 
effectually,  but  the  same  candle  power  bulbs  must  be  used  at  all  times. 

Dash  and  Tail  Lamps. — These  are  frequently  so  wired  and  con- 
nected that  one  bulb  burning  out  will  put  both  out  of  commission. 
In  other  words  they  are  wired  in  series.     If  a  6-8  volt  system  is  in 


496 


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use  the  bulbs  for  tail  and  dash  lights  in  series  would  be  3-4  volt. 
In  most  cases  two-candle  power  bulbs  are  used.  Where  this  system 
is  in  use  the  driver  is  aware  instantly  any  trouble  develops  with  the 
tail  light.  This  may  save  him  much  embarrassment  in  night  driving 
to  say  nothing  of  the  added  safety  assured  the  motor  car. 


Wiring  and  Lighting 


497 


498 


Automotive  Trade  Training 


CIRCUIT  DIAGRAM 


Tail  and  dash  lights  are  not  always  in  series,  and  when  this  is 
not  the  case  the  bulbs  are  the  same  voltage  as  the  electric  system. 
The  candle  power  is  two  to  four. 


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500 


Automotive  Trade  Training 


Spot  and  Search  Lights. — These  are  designed  for  use  as  an 
auxiHary  light.  For  roads  not  familiar  to  the  driver  and  in  showing 
up  the  side  of  the  road  when  passing  other  vehicles  they  are  well 
worth  while.  Some  communities  prohibit  their  use,  but  this  is  merely 
because  of  the  unrestrained  and  abusive  use  of  them.  The  safety  of 
the  occupants  of  the  car  is  dependent  on  proper  light  on  the  roadway. 
The  safety  of  the  pedestrian  is  likewise  dependent  on  proper  light, 
but  the  glaring  head  or  spot  light  is  a  source  of  danger  to  both  unless 
the  pencil  of  light  is  kept  below  the  point  of  vision  of  the  approach- 
ing car  or  pedestrian. 

Ammeters. — Nothing  is  more  valuable  to  the  driver  than  an 
ammeter  which  may  be  depended  on.  Its  proper  indication  of  the 
charging  and  discharging  of  the  battery  is  invaluable.  All  current 
passing  from  the  battery  to  the  ignition  or  lighting  circuit  must  first 
pass  through  the  ammeter.  Current  used  to  operate  the  starting 
motor  in  cranking  the  engine  is  not  passed  through  the  ammeter. 


Fig.  593.  Stewart  Spotlight. 


Pig.  594.  Stewart   Searchlight. 


An  instrument  of  sufficient  capacity  to  register  the  output  of  the 
battery  during  the  cranking  operation  would  not  be  delicate  enough 
to  properly  register  the  rate  of  charge  and  discharge  under  normal 
circumstances.  A  good  ammeter  such  as  the  Weston  instrument, 
■with  which  many  cars  are  equipped  and  which  may  be  installed  on 
any  not  so  equipped,  is  shown  in  Fig.  609.  This  instrument  or  its 
equal  will  show  the  operator  of  the  car  many  things  about  the  opera- 
tion of  his  car  which  he  needs  to  have  exact  knowledge  of  in  order 
that  the  entire  electrical  system  may  be  maintained  in  first  class  con- 
dition.    By  keeping  a  careful  mental  record  of  the  proper  reading  of 


Wiring  and  Lighting 


501 


the  ammeter  the  driver  will  be  able  to  recognize  the  following  con- 
ditions : 

1.  The  proper  discharge  when  the  ignition  switch  is  on  and 
when  the  engine  is  idle  or  running. 

2.  The  proper  charge  rate  in  the  daytime  when  the  lights  are 
off  and  the  engine  driving  the  car  at  a  fifteen  mile  rate,  above  or 
below  that  average  point. 

3.  The  proper  charge  rate  at  night  time  when  the  lights  are 
being  used  and  speeds  are  similar. 

4.  The  proper  discharge  with  the  engine  not  running,  when 
headlights  are  bright  and  all  other  lights  are  on.  The  proper  amount 
of  increase  in  discharge  when  a  spot  light  is  added  to  the  regular 
lamp  load. 

5.  The  proper  discharge  when  the  headlights  are  dimmed. 

6.  The  proper  amount  of  current  for  operating  the  horn. 

7.  Whether  there  is  a  variable  contact  in  the  electrical  circuit. 

8.  Whether  the  generator  brushes  are  in  good  order. 

9.  v^hether  the  generator  regulator  is  operating  properly. 

10.  Whether  there  are  certain  types  of  leaks  or  short  circuits 
in  the  electrical  system  when  the  car  is  standing  idle. 


Fig.  595.     Stewart  Electric  Horn. 


Voltmeter. — The  voltmeter  is  not  a  part  of  the  regular  equipment. 
Its  purpose  is  to  show  the  pressure  of  the  electrical  circuit  just  as 
an  air  gauge  shows  the  pressure  in  a  tire  or  in  a  compressed  air  tank, 
its  use  in  making  electrical  tests  is  explained  elsewhere.  Fig.  610 
shows  the  Weston  Voltmeter. 

Junction  and  Fuse  Boxes. — In  certain  systems  as  employed  by 
the  car  manufacturers  all  the  wires  forming  the  lighting  and  ignition 
circuits  (low  tension)  are  brought  together  at  a  central  point  in  a 
fuse  box,  or  junction  box.  At  this  point  the  proper  weight  of  fuse 
is  placed  in  circuit  to  protect  that  part  of  the  system  to  which  the 
wires  lead,  from  injury  due  to  too  heavy  a  discharge  of  current.     Not 


502 


Automotive  Trade  Training 


Fig:.  59G.  Single 
C  o  nt  a  c  t  Bayonet 
Base,  Standard  for 
automobile  lighting. 


all  cars  are  so  equipped  and  where  not  so  cared  for  the  system  is 
frequently  protected  by  one  central  fuse. 

Bulbs  and  Sockets. — The  bayonet  base  has 
come  to  be  adopted  as  standard  for  the  miniature 
bulbs  used  in  automotive  equipment.  The  minia- 
ture bulb  v^ith  the  screw^  base  is  not  used  to  any 
extent  for  this  type  of  work.  Its  use  was  dis- 
continued because  of  the  liability  of  the  vibration 
causing  the  bulb  to  work  out  and  break  contact. 
The  single  contact  bayonet  base  is  proving  the 
most  popular  due  to  greater  simplicity  of  the 
sockets  and  the  entire  wiring  system. 

The  Proper  Lamp  for  the  Service.* — In  the  design  of  miniature 
Mazda  lamps,  it  is  the  aim  to  provide  a  product  which  wil]  operate 
at  an  economic  balance  between  efficiency  on  the  one  hand,  and  lamp 
life  on  the  other.  This  means  that  the  question  of  operating  voltage 
must  receive  close  attention,  for  both  factors  are  very  sensitive  to 
voltage  conditions ;  the  higher  the  voltage  at  which  a  given  lamp  is 
operated,  the  higher  the  efificiency  of  the  lamp  and  the  shorter  its  life. 
For  the  best  performance,  incandescent  lamps  must  be  supplied  with 
constant  voltage  (in  some  cases,  constant  current)  of  the  proper  value. 
Miniature  lamp  service  is,  in  general,  however,  such  that  the  lamps 
must  be  designed  to  give  the  best  possible  operation  over  wid^  ranges 
of  voltage.  The  characteristics  of  the  energy  supply — whether  storage 
cells,  dry  cells,  battery  generator  systems,  magneto,  or  central  station 
service — must  be  carefully  taken  into  account.  Lamps  must  be 
designed  to  operate  efficiently  and  to  give  satisfactory  life ;  they  must 
not  burn  out  in  an  unreasonably^short  time  at  high  voltage  and  they 
must  give  fair  illumination  during-  the  time  they  are  operating  at 
low  voltage. 


o 

JiLSO  NOTANCHOHEO 

rUcimeni   Forms   Used  in  Miniature     M/IZOfI  Ump9 
Fig.   597. 

Design  of  Lamps  for  Use  with  Storage  Batteries. — In  the  design 
of  lamps  for  use  with  storage  cells,  it  is  necessary  to  take  into  con- 
sideration the  voltage  variations  which  occur  throughout  the  entire 
time  of  discharge.  For  example,  a  lead-type  liquid-electrolyte  storage 
cell,  the  type  at  present  most  commonly  used  with  miniature  lamps> 


♦Courtesy,   National  Lamp  Works. 


Wiring  and  Lighting 


503 


4* 

/4 

„ 

'""^ 

*-- 

>, 

1 

f 

) 

r 

&6 

\ 

) 

W 

Fig.  598A.    Storage  Battery  Discharge  Curve. 

has  an  initial  open-circuit  voltage  of  about  2.2  volts  per  cell.  During 
discharge,  this  voltage  rapidly  drops  to  slightly  above  two  volts,  from 
which  point  the  decrease  in  voltage  is  very  slow  and  uniform  for  a 
considerable  period,  depending  upon  the  rate  of  discharge  and  the 
capacity  of  the  battery.  As  the  cell  approaches  exhaustion,  the  volt- 
age again  decreases  very  rapidly.  Due  to  destructive  chemical  action 
which  may  take  place  within  the  cell  near  exhaustion,  it  is  not  con- 
sidered good  practice  to  allow  the  voltage  to  drop  below  about  1.8 
volts,  and  this  value  represents,  therefore,  the  lowest  working  volt- 
age of  the  cell.  The  curve  of  Fig.  598A  is  typical  of  the  continuous 
discharge  characteristics  of  lead-type  liquid-electrolyte  cells  in  gen- 
eral. The  rate  of  discharge  and  capacity  of  the  cell  afifect,  of  course, 
the  voltage  which  the  cell  maintains. 


f^ 

' 

t-Z 

*^ 

-^ 

///n 

/•O 

'"^ 

--. 

Co^ 

Y^£:ic^ 

T"" 

h^ 

pS^^. 

t"^ 

^ 

^^ 

^ 

- 

X 

OA 

M.9 

HOtJR^ 

Fig.   598B.    Typical   continuous   and    intermittent   average   discliarge   voltage   curves    for 
No.  6  dry  cells  discharging  through  miniature  mazda  lamp. 


504  Automotive  Trade  Training 

Another  factor  which  influences  the  design  of  miniature  Mazda 
lamps  is  the  condition  of  charge  of  the  battery  during  the  time  the 
lamps  are  operating.  In  certain  hand  lanterns,  for  instance,  the  lamp 
operates  over  several  complete  discharge  periods  of  the  battery.  In 
electric  vehicle  service,  the  battery  is  seldom  allowed  to  discharge  to 
a  point  near  exhaustion,  and  the  lamps  must  be  designed  therefore  for 
a  higher  average  cell  voltage. 

With  the  conditions  of  service  known,  it  is  possible  to  calculate 
the  voltage  for  which  lamps  should  be  designed  in  order  to  give  the 
desired  average  life  on  that  particular  battery.  Since  these  calcula- 
tions are  somewhat  involved  and  are  influenced  to  a  large  extent  by 
physical  limitations  in  lamp  manufacture,  it  is  requested  that  those 
engaged  in  the  development  of  new  apparatus  employing  miniature 
lamps  consult  the  lamp  manufacturer  at  as  early  a  stage  of  develop- 
ment as  possible. 

Design  of  Lamps  for  Use  vrith  Dry  Cells. — In  the  case  of  dry 
cells  the  individual  voltage  of  the  cells  will  vary  widely,  depending 
upon  the  composition  of  the  cell.  On  continuous  discharge,  where  a 
cell  does  not  get  a  chance  to  recuperate,  the  voltage  will  show  a  con- 
tinuous drop  from  the  initial  voltage.  When  the  cell  is  on  intermit- 
tent discharge,  the  discharge  curve  is  composed  of  a  succession  of 
periodic  discharge  curves,  each  succeeding  curve  having  lower  maxi- 
mum, minimum,  and  average  voltage  values.  Due  to  the  recupera- 
tive action,  the  average  voltage  of  a  cell  in  intermittent  service  may 
be  considerably  higher  throughout  the  useful  life  of  the  cell  than  will 
that  of  one  used  for  continuous  service.  Fig.  598B  shows  typical  in- 
termittent and  continuous  discharge  curves  obtained  from  dry  cells 
discharging  through  Mazda  lamps.  A  period  of  at  least  two  hours 
was  allowed  between  the  periodic  discharges  for  recuperation. 
Experiments  show  that  in  the  ordinary  commercial  cell  after  two 
hours*  recuperation,  further  voltage  rise  and  capacity  increase  are 
negligibly  small. 

In  general,  for  a  given  discharge  rate,  the  shorter  the  periods  of 
service,  the  higher  will  be  the  averages  of  the  periodic  discharge 
voltages  and  the  longer  will  the  cell  maintain  its  voltage.  However, 
when  a  cell  is  allowed  to  stand  unused  for  long  periods,  the  averages 
of  the  periodic  discharge  voltages  may  fall  off  even  more  rapidly  and 
the  useful  life  of  the  cell  be  actually  less  than  with  longer  discharge 
periods  and  shorter  intervals  between  such  periods. 

Before  the  lamp  voltage  best  suited  to  a  dry  battery  can  be 
determined,  it  is  necessary  to  decide  to  what  degree  the  illumination 
may  decrease  from  the  normal  and  still  serve  the  purpose  at  hand, 
to  express  this  in  terms  of  voltage  and  to  consider  the  usefulness  of 
the  battery  at  an  end  when  the  battery  voltage  has  dropped  perma- 
nently below  this  value.    The  procedure  is  as  follows:    The  voltage 


Wiring  and  Lighting 


605 


curve  of  the  particular  type  of  battery  in  question  is  taken  under 
certain  conditions  of  load  from  initial  voltage  to  the  point  where  the 
voltage  has  dropped  to  0.7  volt  per  cell  in  the  case  of  dry  cells  of  the 
standard  No.  6  type  or  to  0.5  volt  in  that  of  flashlight  cells.  The 
voltage  curve  between  these  points,  translated  into  terms  of  lamp 
life,  forms  the  basis  for  the  lamp  design.  The  discard  point  of  the 
battery  is  considered  as  that  point  in  the  discharge  when  the  volt- 
age has  decreased  to  60  per  cent  of  the  mean  effective  lamp  volt- 
age. This  naturally  varies  considerably  in  different  types  of  cells, 
one  of  the  important  factors  being  the  cubical  content.  Lamps 
must  be  designed  in  a  wide  range  of  voltages  to  suit  the  different 
styles  and  capacities  of  dry  cells  in  common  use.  The  voltage  rat- 
ings are,  however,  purely  nominal  and  do  not  represent  the  actual 
design  voltage.  For  example,  at  present,  flashlight  lamps  for  use  on 
two-cell  batteries  have  nominal  ratings  of  2.5,  2.7,  and  2.9  volts 
depending  upon  the  capacity  of  the  battery  with  which  they  are  to 


Fig.    599.    Focus    Adjustment    on    Headlamp    for 
Standardized  Military  Truclc  Class  B. 

be  used.     Periodic  tests  on  batteries  are  conducted  to  insure  a  lamp 
product  suited  to  modern  battery  product. 

Referring  again  to  Fig.  598B  it  is  seen  that  for  all  values  of  volt- 
age higher  than  0.7  volts,  the  average  voltage  curve  on  intermittent 
discharge  lies  above  the  continuous  discharge  curve.  Hence,  a 
greater  proportion  of  the  total  energy  of  the  cell  may  be  utilized  on 
intermittent  service  than  on  continuous  service.  Moreover,  the  varia- 
tion of  voltage  throughout  the  greater  portion  of  the  life  of  the  bat- 
tery is  between  narrower  limits  and  the  candle-power  of  the  lamp  is 
more  nearly  constant. 


506 


Automotive  Trade  Training 


Design  of  Lamps  for  Use  with  Battery — Generator  Systems. — < 
Lead  storage  batteries  in  combination  wtih  generator  systems  are  a 
third  type  of  energy  source  much  used  for  miniature  lamps,  particu- 
larly in  automobile  and  motor-boat  service.  There  may  be  as  much 
as  35  per  cent  difference  betw^een  the  voltages  at  w^hich  the  lamps 
operate  v^hen  the  engine  is  idle  and  the  battery  is  near  exhaustion, 
and  when  the  engine  is  running  and  the  battery  is  in  a  state  of  satura- 
tion. It  is  necessary  to  design  the  lamps  for  such  service  to  give  fair 
illumination  at  a  low  voltage  and  to  give  satisfactory  life  perform- 
ance despite  the  voltage  variations  above  normal.  Large  numbers 
of  tests  conducted  on  a  large  number  of  the  various  makes  of  auto- 
mobiles under  widely  different  conditions  of  service  have  made  pos- 


Esfe'*^' 

■1 

fh 

p^^^^^ 

■ 

1 

^  'Shijum 

M 

I 

1 

1 

i  \ 

-^^ 

^^       ^,^ 

1 

IP^ 

J 

Fig.    600. 


Sectional    View    Cadillac 
Lamp. 


Head       Fig.  601.     Gray  and  Davis  Focusing  Device. 


sible  the  design  of  lamps  adapted  to  battery-generator  systems  where 
the  average  normal  voltage  fluctuation  is  between  6  and  8  volts,  12 
and  16  volts,  and  18  and  24  volts.  Lamps  for  this  service  are  rated 
6-8  volts,  12-16  volts,  and  18-24  volts,  respectively. 

Design  of  Lamps  for  Magneto  Lighting  Systems. — The  straight 
magneto  system  of  energy  supply  is  about  the  most  difficult  system 
existing  for  which  to  design  satisfactory  lamps.  The  voltage  varies 
:n  about  direct  proportion  to  the  speed  of  the  magneto.  The  magneto 
speed  in  turn,  usually  varies  directly  as  the  engine  speed,  with  the 
lesult  that  the  lamp  is  called  upon  to  furnish  illumination  over  an 
extremely  wide  range  of  voltage.  In  the  design  of  lamps  for  mag- 
neto service,  the  aim  is  to  provide  a  lamp  which  will  supply  sufficient 
illumination  at  the  lower  engine  speeds  yet  which  will  not  burn  out 


Wiring  and  Lighting 


507 


in  an  unreasonably  short  time  when  the  engine  is  running  at  high 
speed.  Lamps  which  meet  these  requirements  will  supply  satisfac- 
tory lighting  at  the  usual  running  speed. 

Some  Fundamentals  of  Light  Projection. — A  large  proportion  of 
all  miniature  Mazda  lamps  are  designed  for  use  in  equipments  which 


C  -  SOURCE  IN  FRONT  Of"  FOCU^ 


Fig.  602.     Beam   ckaracteristics  of  Parabolic   Reflector  with   light  sources  in  three 

Positions. 


project  the  light  in  relatively  narrow  beams.  In  flashlight  service,  the 
lamp  is  usually  equipped  with  a  reflector  or  lens  system  which,  while 
directing  the  light  in  a  beam,  does  not  confine  it  closely;  in  headlight 
and  spotlight  service,  the  beam  is  confined  to  a  considerably  narrower 
angle.  In  practically  all  cases,  the  desired  effect  is  secured  through 
the  use  of  a  polished  reflector  of  a  contour  which  confines  the  light 
to  the  desired  angle. 

The  narrowest  beams  of  light  are  obtained  with  paraboloids,  that 
is,  with  reflectors  whose  surface  is  formed  by  revolving  a  parabola 
about  its  axis.'  When  a  source  is  placed  at  the  focus  of  a  parabolic 
reflector,  the  light  rays  striking  the  reflecting  surface  are  projected 


508  Automotive  Trade  Training 

forward  in  a  beam,  the  central  ray  of  which  is  parallel  to  the  axis 

(See  A,  Fig.  602).     When  the  source  is  placed  behind  the  focus,  the 

beams  diverge  as  shown  in  B.     When  the  source  is  in  front  of  the 

focus,  the  beams  converge,  cross,  and  diverge 

as  shown  in  C.     Contrary  to  the  idea  sometimes 

advanced  no  light  is  lost  by  the  crossing  of  the 

beams. 

Every  point  on  the  surface  of  a  parabolic 
projector  reflects  a  cone  of  light  whose  spread 
depends  upon  the  size  of  the  source  and  the 
focal  length  of  the  reflector,  as  shown  in  Fig. 
602.  It  will  be  seen,  in  other  words,  that  the 
spread  of  the  beam  is  determined  by  the  angle  pig.  eos.  Appearance  of 
which  the  light  source  intercepts  at  the  surface  ^p^^  ^""""SeSdHghts  ^^''^"^^'^ 
of  the  reflector.     A  source  which  presents  its 

largest  dimension  toward  a  part  of  the  reflector  remote  from  the  focus 
will,  therefore,  give  a  narrower  spread  of  beam  than  when  it  presents 
the  largest  dimension  to  the  closest  part  of  the  surface.  The  fila- 
ments of  Mazda  lamps  designed  for  headlight  and  spotlight  service 
are  condensed  into  as  small  a  space  as  practical,  and  when  set  at  the 
focus  of  a  parabolic  projector,  provide  a  beam  which  is  very  highly 
concentrated.  A  position  of  the  filament,  either  ahead  of  or  behind 
the  focus,  will  result  in  a  broader  beam ;  but  if.  the  filament  lies 
behind  the  focal  point,  the  reflecting  surface  will  catch  and  reflect  a 
slightly  larger  portion  of  the  light  emitted  by  the  filament. 


Pig.  e04.    Appearance  of   Spot  from  Headlights  with  light  source  too  far  ahead  of  or 

behind  focal  point. 


Wiring  and  Lighting 


509 


The  motorist  should  make  a  very  careful  study  and  adjustment 
ci  his  headlights.  The  adjustment  can  best  be  accomplished  by 
standing  the  car  on  a  level  roadway  and  projecting  the  headlight 
beams,  without  any  glare-reducing  device,  upon  a  flat  surface  perpen- 
dicular to  th'"  axis  of  the  beam,  at  a  distance  of  not  less  than  25  feet. 
The  lamps  .  hould  then  be  adjusted  in  the  reflector  by  means  of  adjust- 
ing screws  or  other  devices  now  furnished  on  all  good  headlights, 
until  the  smallest  spots  of  light  obtainable  are  thrown  on  the  distant 
surface.  The  lamps  will  then  be  at  the  focal  points  of  the  reflectors. 
The  appearance  of  the  spot  of  light  projected  by  each  headlight 
snould  in  this  case  be  approximately  as  shown  in  Fig.  603.  If  the 
lamp  is  too  far  ahead  of  or  behind  the  focus,  the  spot  should  appear 
about  as  in  Fig.  604.  With  the  lamp  in  focus,  careful  measurements 
should  be  made  to  determine  whether  the  centers  of  these  spots  of 
light  are  any  higher  than  the  centers  of  the  headlights  themselves. 
If  they  are,  the  headlights  should  be  bent  down  until  the  centers  of 
the  beams  come  slightly  below  the  horizontal. 

There  are  three  general  types  of  glare-reducing  devices  for  use 
on  automobile  headlights :  One  type  operates  by  diffusing  the  light, 
another  by  refracting  or  reflecting  the  light  rays ;  the  third  by  cutting 
off  the  rays  which  would  be  projected  upward. 

JOB  191.     SPLICING  LIGHTING 
CABLES. 

It  is  frequently  necessary  to  splice 
a  wire  in  order  to  lengthen  it.  Another 
splice  is  the  one  in  which  it  is  necessary 
to  cut  in  on  a  circuit  for  a  branch  to 
some  special  instrument  as  the  search  or 
spot  light. 

1.  In  making  the  end  splice  the  first 
step  is  to  determine  the  length  of  end 
necessary  to  be  exposed  in  order  to 
splice. 

2.,  With  a  sharp  knife  run  a  light 
cut  around  the  wire  at  this  point  just 
cutting  through  the  outer  layer  of  cotton 
covering.  To  make  this  cut  in  a  care- 
less manner  is  certain  to  result  in  sever- 
ing some  of  the  fine  strands. 

3.  Using  the  point  of  the  knife,  split 
the  insulating  material  from  the  first  cut 
made  to  the  end  of  the  cable.  This  ope- 
ration requires  care  as  the  knife  actually 
cuts  down  to  the  wire  strands. 

4.  Open   the   cable   at   the   end   and 
pull  out  the  strands  of  wire  through  the  slit  just  made. 

5.  Use  the  knife  to  finish  the  first  cut  made.  This  is  easily  accomplished 
since  the  cable  strands  are  kept  twisted  together  and  may  thus  be  pulled  away 
from  the  insulation  while  same  is  being  trimmed. 


Fi|r.  605.  Varying  the  Dimming  of 
Headlights.  (Hudson.)  By  tying  two 
of  the  coils  together  the  amount  of 
resistance  wire  in  circuit  on  dimmer  is 
lessened   and   lamps   burn   brighter. 


510 


Automotive  Trade  Training 


I^^^H^^pv 


6.  With  an  end  of  each  length  of  wire  free  of  all  insulation  the  two  are 
twisted  together  in  the  form  best  suited  for  the  work  in  hand. 

7.  Treat    the    splice    with    soldering   paste    and    solder    carefully.     Make 


Wiring  and  Lighting 


11 


certain  that  the  solder  runs  into  the  strands  and  does  not  merely  rest  on  tiie 
outer  surfaces. 

8.  In  making  a  splice  where  the  end  of  the  new  piece  of  cable  is  joined 
onto  the  old  cable,  at  some  point  other  than  the  end,  the  first  step  is  to  remove 
the  cable  insulation  at  the  point  desired  to  tap  in  on  the  main  circuit.  Do  this 
work  most  carefully  in  order  that  not  one  of  the  small  strands  is  injured. 
Make  the  splice,  solder  and  tape  as  suggested  above. 


JOB  192.     SWEATING  OR  BURNING  ON  A  TERMINAL. 

It  is  frequently  necessary  to  sweat  or  burn  on  a  new  terminal  for  some  of 
the  leads  of  the  electric  system.  This  work  may  be  necessary  in  reference  to 
the  storage  battery  terminals  or  any  of  the  numerous  terminals  such  as  are' 
found  about  the  ammeter,  the  generator,  or  the  starter.  Burning  or  sweating 
in  this  case  means  having  the  solder  worked  while  in  the  liquid  or  melted 
state. 

1.     Select  the  new  terminal  with  reference  to  the  requirements  of  the  job. 

Where  the  old  is  still  in  such 
condition  as  to  permit  of 
comparison,  the  new  terminal 
should  be  matched  to  it. 

2.  Prepare  the  cable  by 
removing  as  much  of  the  in- 
sulation as  may  be  necessary 
to  permit  the  strands  to  en- 
ter the  terminal  properly. 

3.  Twist  the  strands  to- 
gether and  tin  them.  To  do 
this  they  must  be  clean.  The 
soldering  iron  may  be  used 
to  flow  the  solder  onto  the 
cable  end;  the  end  may  be 
treated  with  soldering  flux 
and  dipped  into  a  pot  of 
melted  solder,  or  the  end 
may  be  tinned  by  the  use  of 
the  lead  burning  or  other 
light  flame. 

4.  Next  prepare  the 
terminal  by  tinning  the  in- 
side of  it  and  running  it  full 
of  melted   solder. 

5.  Keep  the  terminal 
hot.  The  end  of  the  cable 
previously  tinned  is  heated 
and  the  two  while  hot 
are  forced  together.  This 
will  crowd  out  some  of  the 
solder  in  the  terminal,  but  it 
is  better  to  have  too  much 
solder  than  not  enough. 

6.  When  cool,  the  job 
should  be  cleaned  and  taped 
if  necessary. 


Fig.  607. 


Reverse  side  of  Weston  Ammeter, 
terminals  and   binding   posts. 


Note 


_0 


•  TO  rH£  UGHTtNG  SYSr£M 

TO  fGNfr/ON  srsr£M 


/9AfM£r£/9    cur-our 


BATTERY 


## 


GENERATOR 


f 


3 


Fig.   608. 


Sugjrestive    diajrram    for   wiring   an 
ammeter.     (Weston.) 


512 


Automotive  Trade  Training 


JOB  193.     ATTACHING  WIRES  TO  LAMP  SOCKETS. 

1.  Remove  the  insulation  for  such  a  distance  as  is  necessary  to  expose 
enough  cable  to  enter  into  the  socket. 

2.  Sweat  the  ends  of  the  stranded  cable  together.     (Job  192.) 

3.  Carefully  insert  the  sweated  ends  of  the  cable  into  the  small  tubes 
mounted  in  the  sockets.  Make,  certain  that  the  small  set  screw  is  backed  out 
sufficiently  to  allow  the  cable  end  to  enter.  Use  a  small  screw  driver  for  this 
screw,  otherwise  the  hard  rubber  socket  may  be  broken. 

4.  When  all  is  properly  assembled,  tighten  the  binding  screw. 

5.  Never  pull  or  jerk  on  the  lamp  wires  as  they  are  subject  to  injury. 
They  may  be  pulled  from  the  socket  if  roughly  handled.  The  hard  rubber 
nut  fitted  onto  the  end  of  the  socket  should  always   be  kept  turned  up  snug. 

JOB  194.     INSTALLING  AND  WIRING  AN  AMMETER. 

1.  In  some  cases  cars  are  not  equipped  with  an  ammeter.  To  install  one, 
first  select  the  instrument  of  a  style  suitable  to  mounting  in  the  space  available. 
Where  an  ammeter  is  placed  in  circuit  instead  of  the  "telltale"  or  "ofif  and  on" 
instrument  the  same  wiring  may  be  used. 

2.  Cut  the  instrument  or  dash  board  to  permit  of  mounting  the  ammeter 
selected. 

3.  Learn  the  most  suitable  points  to  cut  in  on  the  circuit  between  the 
battery  and  the  lighting  and  ignition  leads.  All  current  used  should  be  made  to 
pass  through  the  ammeter,  excepting,  of  course,  the  starting  current  which  is 
very  heavy. 

4.  Consult  the  wiring  diagram,   Fig.   608. 

5.  Solder  and  tape  all  splices. 

6.  Secure  all  cables  so  that  they  are  free  of  oil,  grease,  or  dirt  and 
likewise  of  the  danger  of  mechanical  disarrangement  and  injury. 

7.  Test  the  instrument  when  all  connections  are  made.  If  it  shows 
charge  when  the  lights  are  burning  and  the  engine  idle,  the  wires  on  the  back 
of  the  instrument  will  want  to  be  changed,  or  reversed.  If  it  shows  discharge, 
the  connection  is  correct.  Fig.  607  shows  these  connections  or  binding  posts 
and  screws  on  the  back  of  the  ammeter. 


Fig.  609. 


Weston  Ammeter  for 
mounting. 


Fig.    610.     Weston   Voltmeter. 


Wiring  and  Lighting 


513 


JOB  195.     POLISHING  LAMP  REFLECTORS. 

Lamp  reflectors  are  made  from  brass,  silver  plated,  then  polished  very 
highly.  The  secret  of  keeping  them  bright  and  in  good  condition  is  keeping 
the  air  excluded.  Excluding  the  air  by  means  of  properly  fitted  dust  rings 
means  that  the  moisture  and  road  dust  will  not  be  carried  in  as  is  the  case 
where  the  small  currents  of  air  find  their  way  into  the  lamp.  In  case  they  do 
become  dusty  the  best  way  to  remove  the  dust  is  by  means  of  blowing  it  away. 
A  stream  of  compressed  air  is  best  for  this.  Where  the  reflector  is  old  and 
tarnished  it  may  be  necessary  to  remove  and  repolish  it.  Hand  polishing  will 
not  restore  the  original  luster  but  may  result  in  a  temporary  improvement. 

Not  all  mechanics  nor  lamp  manufacturers  are  agreed  on  the  proper 
method  to  follow  in  polishing  the  reflectors  when  this  work  is  done  by  hand. 
The  following  method  is  the  one  recommended  by  the  Gray  and  Davis  Co. 

1.  Use  crocus  or  rouge  with  a  clean  chamois.  Have  the  chamois  free  of 
dust  and  retain  it  for  this  purpose  alone. 

2.  To  polish  use  the  chamois  with  rouge  dampened  with  alcohol.  This 
will  remove  the  heavier  spots  of  tarnish. 

3.  After  this  is  all  wiped  off  with  the  first  piece  of  chamois,   a   second 
piece  is  used   with   dry   rouge, 
to    give    the    reflector    a    very 
high  polish. 

4.  In  polishing  use  a  ro- 
tary motion  as  indicated  in 
Fig.  611. 

Not  all  workmen  favor 
the  rotary  motion  for  polish- 
ing reflectors.  A  motion  di- 
rected from  the  rim  of  the  re- 
flector to  the  center  is  less 
likely  to  leave  marks.  How- 
ever, either  a  perfect  rotary 
motion  or  a  direct  in  and  out 
motion  should  be  used  and  no 
attempt  made  to  change  pro- 
miscuously from  one  to  the 
other.  Neither  may  good  re- 
sults be  expected  if  a  haphaz- 
ard hit  or  miss  sort  of  effort 
is  made.  Where  the  chamois 
and  rouge  are  not  available, 
good  results  may  be  obtained 
from  the  use  of  lamp  black  and  a  fine  grade  of  tissue  paper.  Many  other 
methods  of  greater  or  lesser  value  are  in  use.  As  a  final  word  of  caution  it  is 
suggested  that  whatever  materials  or  polishing  stroke  is  used  that  the 
pressure  be  not  too  great. 

Resilvering  of  the  reflectors  is  work  always  handled  by  the  lamp  manu- 
facturers or  the  plating  establishments. 


Fig.    611.     Polishing    Lamp    Reflectors. 


JOB  196. 

None  of  the  Lights  Operate. — If  none  of  the  lights  operate  either  the 
battery  is  run  down,  or  there  is  an  open  circuit  between  the  lighting  switch 
and  the  battery.  Connect  the  voltmeter  across  the  battery  as  shown  in  Fig. 
612,  using  the  30-volt  range. 

The  reading  of  the  voltmeter  is  the  open  circuit  voltage  of  the  battery. 


514 


Automotive  Trade  Training 


UI^HMQ 


^mrcH 


\ 


I 


I         <l)       o         n  k 


^^ 


Fig.    612. 

Now  close  the  lighting  switch.  If  this  is  in  poor  condition  the  indication  will 
drop  a  considerable  amount.  Should  this  be  the  case  apply  tests  given  in 
Chapter  11,  to  the  battery. 

If  the  indication  does  not  change  when  the  switch  is  closed  change  the 
voltmeter  connection  as  shown  in  Fig.  613. 

No  indication  denotes  an  open  circuit  between  the  lighting  switch  and  the 
battery. 


Fig.  613. 


Wiring  and  Lighting 


515 


Fig.   614, 

JOB  197. 

Head  Lights  or  Side  Lights  Not  Operating. — On  a  six-volt  system  the 
head  lights  and  the  side  lights  are  connected  in  multiple  as  shown  in  the 
several  illustrations.  If,  therefore,  one  of  the  headlights  or  side  lights  does 
not  operate,  and  the  other  does,  the  trouble  is  very  likely  to  be  a  burned  out 
light. 


Pig.  615. 


516 


Automotive  Trade  Training 


If  both  head  lights  or  both  side  lights  do  not  operate,  the  probability  is 
that  they  are  not  getting  the  voltage  they  require. 

In  this  case  the  30-volt  range  of  the  voltmeter  should  be  connected  across 
the  contacts  of  the  lighting  switch  as  shown  in  Fig.  614,  which  is  the  test  for 
trouble  in  the  head  light  circuit.  If  the  side  lights  are  inoperative  the 
connection  should  be  made  across  the  switch  for  that  circuit. 

With  the  switch  open  the  voltmeter  should  indicate  the  battery  voltage. 
If  it  does  not,  change  the  lamps  to  see  if  they  are  burned  out.  If  the  system 
is  fused,  look  for  burned  out  fuses. 

If  the  reading  is  equal  to  the  battery  voltage  close  the  switch;  the  reading 
should  now  be  zero,  otherwise  the  contacts  do  not  close  or  they  are  in  bad 
condition. 

If  the  indication  does  not  drop  to  zero,  since  the  lights  do  not  burn,  the 
chances  are  that  there  is  a  short  circuit.  This  can  be  determined  by  applying 
the  test  given  in  Job  198. 

JOB  198. 

Short  Circuit  in  Branch  of  Lighting  Circuit. — The  30-volt  range  is  con- 
nected across  the  branch  circuit  as  shown  in  Fig.  615. 

If  there  is  a  short  circuit,  the  indication  will  be  zero  or  nearly  zero.  If 
in  good  condition  the  battery  voltage  will  be  indicated. 


Fig.    616. 
JOB  199. 

One  Headlight  or  One  Side  Light  not  Operating. — As  stated  in  Job  197, 
the  trouble  is  probably  due  to  a  burned  out  lamp  and  the  quickest  test  is  to 
replace  the  lamp  by  a  new  one. 

If  the  trouble  still  exists,  then  connect  the  30-volt  range  of  the  instrument, 
as  shown  in  Fig.  616,  across  the  lamp  receptacle.  With  the  lighting  switch 
closed,  the  voltmeter  should  show  the  battery  voltage. 


Wiring  and  Lighting 


517 


If  the  indication  is  zero  the  lamp  is  not  getting  any  voltage.  The  wires 
leading  into  the  receptacle  should  be  examined  for  open  circuits. 

If  an  indication  is  obtained  the  trouble  may  be  that  the  lamp  is  not  making 
contact  with  the  points  in  the  receptacle,  or  that  it  is  for  a  higher  voltage. 

JOB  200. 

Tail  Light  or  Cowl  Light  Not  Operating. — In  some  systems  of  wiring  the 
tail  and  cowl  lights  are  in  series  and  controlled  from  the  same  switch,  as 
shown  in  the  illustrations  used  in  this  book.  With  this  system  of  wiring,  if 
one  of  the  lights  becomes  defective  the  other  will  not  light  either.  The 
simplest  test  is  to  replace  one  of  the  lights  with  a  new  one.  If  this  does  not 
eliminate  the  trouble  replace  the  other  one  with  a  new  one.  If  the  trouble 
still  is  present,  test  each  receptacle  for  voltage  as  in  test  199. 

If  no  indication  is  obtained  on  either  receptacle  look  for  an  open  circuit 
somewhere  in  the  wiring. 

Other   systems   control   the   tail  light   from   the   head   light   or   side   light 


Fig.   617. 

switch.  In  this  case  tests  198  and  199  should  be  used  to  determine  the  trouble. 
When  such  a  system  of  control  is  used  the  cowl  light  has  its  own  switch  and 
should  be  considered  as  an  individual  circuit  and  tests  197,  198  and  199  should 
be  employed. 


JOB  201. 

To  Measure  the  Current  Taken  by  the  Lights. — Connect  the  ammeter  as 
shown  in  Fig.  617  so  that  it  will  be  in  circuit  between  the  battery  and  lighting 
switch.  As  shown  with  all  switches  closed,  the  total  lighting  current  will  be 
indicated.  If  individual  switches  are  operated  separately  the  current  for  any 
particular  circuit  can  be  determined,  and  in  the  case  of  lamps  in  parallel  the 
current  for  an  individual  lamp  can  be  determined  by  removing  the  one  in 
parallel  with  it.  This  test  will  be  found  of  importance  when  the  various  lights 
do  not  burn  with  equal  intensity. 


CHAPTER  16 
TIRE  CARE  AND  VULCANIZING 

*THE  PRINCIPLES  OF  TIRE  CONSTRUCTION 

Fabric  Tires. — Although  there  are  many  different  methods  of 
vulcanizing  tires,  the  methods  used  may  be  classified  under  the  gen- 
eral headings  of  ''single  cure"  and  "double  cure". 

In  the  case  of  "single  cure"  fabric  tires,  the  method  of  building 
up  is  as  follows : 

The  foundation,  or  carcass,  of  the  fabric  tire  is  built  up  of  close- 
woven  fabric.  This  fabric  is  thoroughly  impregnated  with  rubber 
compound  and  cut  in  strips  on  the  bias  to  the  proper  width  to  cover 
the  iron  core  on  which  the  tire  is  to  be  built.  When  the  layers  of 
fabric  going  under  the  bead  have  been  applied  to  the  iron  core  the 
bead  is  placed  in  position  and  the  remaining  layers  of  fabric,  going 
into  the  tire,  are  added. 

The  plies  of  fabric  are  then  stitched  over  the  bead,  alternately, 
and  trimmed.  A  chafing  strip  of  light  fabric  is  applied  over  the  bead 
extending  from  the  toe  of  the  bead  to  a  point  i^"  to  ^"  above  the 
bead  proper. 

The  cushion,  breaker,  side  walls,  and  tread  are  then  applied  and 
the  tire  placed  in  a  mold,  in  which  the  non-skid  pattern  of  the  tread 
is  cut,  and  cured. 

Sometimes  the  iron  core  is  removed  and  replaced  by  an  air  bag 
which  is  inflated  before  curing. 

In  the  case  of  "two-cure"  tires  the  carcass  is  built  up  in  the 
manner  described  above ;  the  side  walls  and  top  covers  are  put  on  and 
the  tire  is  put  in  a  mold  and  given  a  semi-cure  in  order  to  set  the 
fabric  carcass.  The  cushion,  breaker,  undertread  and  semi-cured 
tread  band  are  then  put  on,  the  tire  is  wrapped  and  given  a  final  cure 
by  hanging  the  tire  in  a  heater.  Sometimes  the  cushion  and  breaker 
are  put  on  and  cured  in  the  first  cure. 

There  are  two  methods  of  handling  the  tires  during  the  second 
cure.  In  one  case  the  tire  is  allowed  to  remain  on  the  core  during 
its  entire  construction,  being  cross  wrapped  on  the  core  for  second 
cure.  In  the  second  method  the  core  is  replaced  by  an  air  bag 
and  the  tire  is  put  on  a  curing  rim  before  being  wrapped.  The  bag 
is  then  inflated. 

Cord  Tires. — The  manufacturing  operation  in  the  case  of  cord 
tires  is  very  much  the  same  as  for  fabric  tires.  They  are  usually 
cured  by  some  internal  pressure  process,  such  as  the  air  bag. 


♦Courtesy  Goodyear  Tire  &  Rubber  Co. 

518 


Tire  Care  and  Vulcanizing 


519 


The  chief  difference  in  a  cord  tire  is  that  the  carcass  is  built  up 
of  what  is  known  as  cord  fabric.  This  is  a  fabric  made  up  of  cords 
all  parallel  to  one  another  and  held  in  place  by  a  few  light  "tie-in'* 
cords. 

The  patented  Goodyear  method  of  building  cord  tires  reduces 
the  friction  to  a  minimum  between  these  cords,  thus  greatly  increas- 
ing the  mileage  delivered,  and  facilitating  repair  work. 

This  construction  is  briefly  as  follows :  Four  groups  of  plies  are 
used,  separated  from  each  other  by  a  thin  cushion.  In  each  group 
the  number  of  plies  depends  on  the  size  of  the  tire.  The  different 
plies  are  put  on   so  that  the  cords  in  each  group  run  in  the  same 


Bead. 

Layer  of  fabric. 
Flipper  strip. 
Chafing  strip. 
Cusliion   stock. 
Breaker. 
Under-cover. 
Side  wall. 
All-weather  tread. 


hig.  618.     Fabric  Tire  Construction. 
(Courtesy  Goodyear  Tire  &   Rubber  Co.) 

direction.  The  direction  of  the  cords  is  changed  in  each  group  so 
that  the  cords  of  one  group  run  at  90°  to  the  cords  in  a  corresponding 
group. 

Fig.  620,  cord  tire,  shows  the  construction  labeled  the  same  as  the 
fabric  tire. 

Tire  Care. — The  realization  of  just  how  much  the  proper  care  of 
tires  means  to  the  user  in  eliminating  trouble  and  excessive  costs  of 
tire  service  is  the  biggest  step  in  securing  absolute  satisfaction.  For 
best  service  note  the  following  suggestions : 

Truing  Up  Wheels. — Often,  through  an  accident  of  some  sort,  a 
misalignment  of  some  kind  occurs  and  one  tire  is  forced  to  slide  or 
scrape   sideways   over   the   ground   instead   of   running  in   a   natural 


520 


Automotive  Trade  Training 


4Pfy  5Ply  7Ply 

Construction  of  Tires  at  Bead 

FahvicS,S. 


manner,  because  the  wheel  itself  does  not  run  true.     The  axle  may  be 

bent  up  or  down,  or  forward  or  backward,  so  that  the  wheel  slants 

or  wabbles  as  it  runs.     The 

rapid  wear  on  the  tread  of  X  X  *■* 

such  a  tire  will  continue  un-  j^\  ff\ 

til  a  mechanic  realigns  the 

wheels. 

Tread  Cuts. — The  knowl- 
edge of  how  to  care  for  tread 
cuts  is  of  the  greatest  im- 
portance to  tire  users.  Every 
sharp  object  the  tire  passes 
over  may,  if  hit  squarely,  in- 
flict a  cut  which,  if  neglected, 
will  cause  the  loss  of  many 
tire  miles.  This  should  be 
carefully  inspected  at  regu- 
lar intervals  and  if  these 
small  cuts  are  found,  they 
should  be  cleaned  out, 
cemented  and  filled  with  tire 
putty.  This  keeps  out  all 
moisture   and   dirt   which   it 

allowed  to  remain,  would  cause  ply  separation  and  a 
the  fabric,  with  an  inevitable  blow-out. 

Inflation. — Gaining  mileage  by  proper  inflation  is  possibly '  the 
most  important  consideration  in  the  care  of  tires.  Plies  of  fabric  or 
layers  of  cords  will  not  continue  to  bear  the  weight  of  a  car  with 
excessive  bending  or  flexing.  The  eflFect  is  the  same  as  when  one 
sharply  bends  a  wire  back  and  forth.  The  air  should  sustain  the 
weight.  The  tire  is  only  a  container.  Each  tire  is  built  to  carry  a 
maximum  load  with  a  minimum  air  pressure. 

Fabric  Breaks. — Fabric  breaks  are  caused  by  hitting  some  object 
which  flexes  the  tire  to  the  breaking  point  at  any  point  in  the  tire. 
It  is  also  caused  by  overload  or  under-inflation.  This  break  occurs 
on  the  inside  of  the  tire  and  may  appear  as  a  slight  wavy  line  on  the 
inside  ply,  or  an  open  break  in  the  plies.  The  proper  care  of  these 
fabric  breaks  is  valuable  information.  The  casing  should  be  exam- 
ined frequently  and  if  a  fabric  break  is  indicated  on  the  inside  a 
sectional  or  full  circle  reliner  should  be  inserted  until  a  permanent 
repair  can  be  made.     An  outside  protector  may  'also  be  necessary. 

TIRE  REPAIR  MATERIALS 

The  Goodyear  line  of  repair  materials  is  shown  here  in  order 
that  the  student  may  familiarize  himself  with  the  trade  names  and 


6  Ply  4  Ply  Clincher  8  Ply 

Cord  S.S.  and  Clincher 

Fig.   619. 

weakenins:  of 


Tire  Care  and  Vulcanizing 


521 


methods  of  listing  the  various  gums,  cements,  and  other  materials 
used  in  the  repair  of  tires.  The  repair  materials  described  are  repre- 
sentative of  best  practice  in  the  tire  repair  business.  Other  com- 
panies manufacture  similar  materials  but  they  would  not  bear  the 
same  catalog  numbers  as  those  shown  for  the  Goodyear  line. 

Tread  Gums. — G-lOO,  G-105  and  G-115  tread  stock  are  used  for 
tread  repairs,  side  wall  repairs  and  as  an  under  cover  stock.  It  may 
also  be  used  in  making  negative  pads  for  preserving  tread  designs. 


Bead. 

Layer  of  cord  fabric^ 

Flipper   strip. 

Chafing   strip. 

Cushion   stock. 

Breaker. 

Under-cover. 

Side  wall. 

All-weather  tread. 


Fig.    620.     Cord   Tire   Construction. 

G-100. — G-lOO  White  Tread  Gum  is  exceedingly  durable,  possess- 
ing the  three  essential  qualities — toughness,  strength  and  resiliency. 
It  also  flows  readily  in  the  "cure". 
Furnished  as  follows : 

5  pound  cartons,  12"  wide. 
12^  and  25  pound  rolls,  18"  wide. 
50  and  100  pound  rolls,  36"  wide. 
Standard  gauge,  1/16". 
G-105. — G-105  Black  Tread  Gum  is  in  great  demand  owing  to 
the  predominance  of  black  tread  tires.     It  is  "tacky"  and  pliable  be- 
fore it  is  cured.     It  flows  easily  and  smoothly  during  the  cure.     It  is 
tough,  strong  and  resilient  after  it  is  cured.     This  gum  has  been  so 
compounded  that  it  will  not  bloom  out  readily. 
See  Camel  Back. 


522 


Automotive  Trade  Training 


Furnished  as  follows: 

5  pound  cartons,  12"  wide. 

I2y2  and  25  pound  rolls,  18"  wide. 

50  and  100  pound  rolls,  36"  wide. 

Standard  gauge,  1/16". 
G-115. — G-115  Grey  Tread  Gum  is  a  tough  and  resilient  stock 
which  flows  easily  and  smoothly  during  the  cure. 
Furnished  as  follows : 

5  pound  cartons,  12"  wide. 

12^/2  and  25  pound  rolls,  18"  wide. 

50  and  100  pound  rolls,  36"  wide. 

Standard  gauge,  1/16". 


Camel  Back,   showing  various   sectional   measurements. 


Camel  Back. — The  Camel  Back  has  been  developed  to  take 
care  of  the  increasing  demand  for  a  tread  stock  ready  for  application. 
Goodyear  Camel  Back  is  so  compounded  that  it  combines  all  of  the 
qualities  incorporated  in  a  perfect  wearing  tread  gum.  Its  design 
is  such  that  it  gives  perfect  results  when  cured  in  the  third  circle 
retread  mold.  Goodyear  Camel  Back  is  black  and  of  the  same  com- 
pound as  G-105  Tread  Gum. 


Furnished  as  follows : 
No.  1  Style  for  3", 
No.  2  Style  for  4", 
No.  3  Style  for  5" 


3^"  tires,  15  and  25  pound  rolls. 

4^"  tires,  15  and  25  pound  rolls. 

tires,  15,  25  and  50  pound  rolls. 
Cushion  and  Tube  Repair  Gum,  G-170. — G-170  is  a  cushion  stock 
of  highest  quality,  being  practically  a  pure  gum  with  just  enough 
compound  to  effect  the  cure.    It  is  strong,  lively  and  resilient,  thereby 


Tire  Care  and  Vulcanizing  523 

possessing  all  of  the  necessary  qualities  to  make  it  desirable  for  a 
good  cushion  stock.  It  may  be  used  in  repairing  inner  tubes  and 
when  properly  dissolved  makes  a  good  cement. 


Fig.  622.    Tread  and  Sidewall  Gum. 

Furnished  as  follows: 

5  pound  cartons,  12"  wide. 
\2y2,  25  and  50  pound  rolls,  18"  wide. 
Standard  gauge,  1/32". 
G-180. — G-180  is  a  quick  cure  gum  for  tube  repairing.     It  is  so 
compounded  that  it  will  cure  in  five  to  ten  minutes  at  60  pounds  steam 
pressure  or  307.2  degrees  Fahrenheit.     The  use  of  G-180  in  repairing 
tubes   lessens   the   chance   of   burning   the    tube.     It   is    particularly 
recommended  for  this  kind  of  work.     It  stretches  with  the  tube  and 
will  not  pull  loose  at  the  edges,  chip,  or  crack. 
Furnished  as  follows : 

1  pound  cartons,  5"  wide. 
5  pound  cartons,  12"  wide. 
12^  and  50  pound  rolls,  18"  wide. 
Standard  gauge,  1/32". 
G-190. — G-190  Cured  Back  Tube  Gum  is  a  combination  of  cured 
and  uncured  stock.     It  is  so  compounded  that  it  will  stretch  with  the 
tube  but  is  tough  and  strong  and  makes  an  excellent  reinforcement. 
This  gum  is  for  inside  reinforcement  on  tube  repairs — using  G-180 
for  outside  work. 

Furnished  as  follows: 

1  pound  cartons,  5"  wide. 
5  pound  cartons,  12"  wide. 
121^,  25,  50  and  100  pound  rolls,  36"  wide. 
Standard  gauge,  6/128". 
Repair  Fabrics,  HF-41. — HF-41  Repair  and  Rebuilding  Fabric  is 
a   14-ounce,   closely   woven   Egyptian   fabric,   impregnated   with   the 
finest  quality  friction.     The  fibres  of  the  fabric  are  actually  1^"  long. 


524 


Automotive  Trade  Training 


The  friction  is  practically  pure  gum.     Such  a  combination  insures 
strength  and  durability.     This  fabric  should  always  be  cut  on  the  bias. 
Furnished  as  follows: 
Friction  two  sides. 
Bareback  (frictioned  one  side  only). 
Frictioned  two  sides,  skim-coated  one  side. 
5  pound  cartons,  12"  wide  (cut  on  bias). 
\2y2  and  25  pound  rolls,  40"  wide. 
LF-52. — LF-52  Bead  Fabric  is  a  strong  7^^  ounce  fabric  impreg- 
nated with  fine  quality  friction. 

It  has   three  purposes,   being  highly   efficient  as   a  bead  cover 
fabric,  a  motorcycle  tire  rebuilding  fabric,  and  a  bicycle  tire  rebuilding 
fabric.     It  is  also  used  as  a  backing  for  negative  pads. 
Furnished  as  follows : 

2^  pound  cartons  (cut  on  bias),  12"  wide. 
Also  furnished  in  12 j^,  25  and  50  pound  rolls,  60"  wide. 
CF-44. — CF-44  Cord  Fabric  is  made  up  of  materials  similar  to 
those    used    in    Goodyear    Cord    Tire    construction.     It    is    used    for 
making  small  inside  reinforcements  that  are  too  small  to  warrant  the 
expense  of  a  cord  patch,  and  for  making  large  sectional  repairs  in 
cord  tires  where  the  injury  in  the  carcass  is  too  extensive  to  be 
repaired  with  a  cord  patch. 
Furnished  as  follows: 

5  pound  rolls,  12"  wide. 

\2y2y  25  and  50  pound  rolls,  48"  wide.  V 


Fig.   623.    Tube   Repair  Gum. 


BF-23. — BF-23  Breaker  Fabric  is  made  up  of  a  high  quality 
fabric,  frictioned  both  sides,  skim  coated  both  sides  with  a  gum  of 
the  same  compound  as  G-170.     This  insures  the  best  possible  union 


Tire  Care  and  Vulcanizing  525 

between  the  cushion  and  breaker,  and  the  breaker  and  tread  or  under- 
tread. 

Furnished  as  follows : 

5  pound  rolls,  12"  wide. 
I2y2  and  25  pound  rolls,  48"  wide. 
Cord  Patch. — Goodyear  Cord  Patch  offers  one  of  the  most  satis- 
factory and  also  the  simplest  method  of  making  a  permanent  repair 
of  ordinary  carcass  injuries  in  fabric  and  cord  tires.  The  Cord  Patch 
properly  vulcanized  usually  outlasts  the  rest  of  the  tire,  and  adds 
many  tire  miles. 

It  is  a  sectional  reinforcement,  for  inside  application,  consisting 
of  several  layers  of  cord  fabric  such  as  is  used  in  the  construction  of 
Goodyear  Cord  tires.  Full  instructions  for  application  are  furnished 
with  each  patch. 

Furnished  as  follows: 

No.  1  for  3^"  and  4"  tires. 
No.  2  for  4>4"  and  5"  tires. 


Fig.  G24.     Repair  Fabric. 

Vulcanizing  Cement,  C-15. — C-15  Cement  is  made  of  the  highest 
quality  materials  and  is  of  a  heavy  consistency.  One  gallon  will 
make  two  gallons  of  good  cement  when  thinned  down  with  a  good 
solvent. 

Furnished  as  follows : 

Pint  cans,   1  gallon  cans  and  5  gallon  cans,  55  gallon  steel 
drums. 

C-16. — C-16  Cement  is  the  same  as  C-15.  It  has  been  thinned  to 
the  proper  working  consistency.  This  cement  is  furnished  because 
many  repair  men  find  it  difficult  to  obtain  a  high  grade  solvent  for 
thinning  C-15  Cement. 


526 


Automotive  Trade  Training 


Furnished  as  follows : 

1  gallon  and  5  gallon  cans. 
55  gallon  steel  drums. 
C-25. — C-25  Cement  is  a  quick  cure  vulcanizing  cement  especially 
compounded  for  use  with  G-180  and  G-190  Tube  Repair  Gums.     It  is 
also  used  in  the  application  of  Goodyear  Cord  Patches. 
Furnished  as  follows : 

1  pint  cans,  1  gallon  and  5  gallon  cans. 
55  gallon  steel  drums. 
C-35. — This  cement  is  of  the  finest  quality  and  is  used  for  apply- 
ing valve  patches,  splicing  inner  tubes,  applying  cold  patches  of  any 
description  and  reliners.     It  is  a  self-curing  cement. 
Furnished  as  follows : 

1  pint,  1  gallon  and  5  gallon  cans  and  55  gallon  steel  drums. 


^OOD^EAR 

C-16 


lizing  Ceme 


'-—-J         C-15 
uicanizing  Cem*^ 


ellt       !  Goodyear  Tire  &  ^^ 


Fig.   G25.     Regular  Cure  Vulcanizing  Cement. 

Reliners. — The  Goodyear  Reliner,  properly  applied,  acts  as  a  new 
backbone  to  a  "worn"  casing  and  usually  adds  many  miles  to  its  life. 
Furnished  as  follows : 
30  X  3        3  ply 
30  X  31^    3  ply 
32  X  3>^    3  ply 
31x4        4  ply 

Goodyear  Reliners  are  made  of  high  grade,  new  American  fabric. 
The  ends  and  sides  are  stepped  down  to  a  feather  edge.  The  ends 
have  rubber  tips  which  prevent  chafing  where  the  ends  lap. 

Valve  Patches. — The  patches  are  made  of  tough  resilient  rubber. 


30x3 

3  ply 

32x4 

4  ply 

35x4^ 

4  ply 

30x31^ 

3  ply 

33x4 

4  ply 

36x4>4 

4  ply 

32x3>^ 

3  ply 

34x4 

4  ply 

35x5 

4  ply 

31x4 

4  ply 

34x41^ 

4  ply 

37x5 

4  ply 

Tire  Care  and  Vulcanizing  537 

reinforced  in  the  center  with  two  pHes  of  fabric.     They  are  rigid  next 
to  the  valve,  but  the  edges  stretch  readily  with  the  tube. 

Furnished  as  follows : 

No.  1  for  3",  3>^",  4",  4>4"  and  5"  tubes. 

Semi-Cured  Retread  Bands. — Goodyear  Retread  Bands  are  of  the 
same  quality  and  dimensions  as  the  treads  on  Goodyear  Tires  and 
excel  in  wearing  qualities,  construction  and  appearance. 

Goodyear  Retread  Bands  give  exceptional  service  when  applied 
with  under-cover  stock  (G-lOO,  G-105  and  G-115)  and  are  cured 
properly.  The  system  of  grouping  sizes  enables  the  repairman  to 
take  care  of  all  passenger  car  size  tires  by  stocking  only  five  sizes 
and  two  styles  of  retread  bands. 

These  bands  may  be  had  in  either  the  All-Weather  or  Ribbed 
Tread. 

Soapstone. — Goodyear  Soapstone  is  the  best  grade  that  can  be 
purchased.  It  should  be  used  in  the  form  of  a  stiff  paste  to  preserve 
tread  designs,  and  to  dust  over  repairs  to  prevent  them  from  adhering 
to  the  molds  and  inner  tubes. 

Furnished  in : 

25  pound  sacks. 


Fig.  626.     Sectional  Air  Bag. 

Sectional  Air  Bags. — Goodyear  Sectional  Airbags  are  made  of  a 
specially  compounded  gum  and  high  grade  closely  woven  fabric.  The 
inside  is  lined  with  a  heavy  gum  tube  especially  compounded  to 
retain  its  good  qualities  even  after  long  continuous  use. 

The  bag  is  reinforced  at  each  end  with  a  reinforcement  of  heavy 
fabric.  A  loop  of  tape  is  attached  to  facilitate  removing  the  bag  from 
the  casing.  Instructions  as  to  the  proper  use  and  care  of  sectional 
airbags  are  furnished  with  each  bag. 

Furnished  as  follov^,  in  ^4  circle  and  1/5  circle: 
3';,  Sy/,  4",  4^",  5"  and  53^"  bags. 

WHY  REPAIRS  FAIL 

Most  repair  failures  are  due  largely  to  oversights  and  careless- 
ness on  the  part  of  the  repairman.  They  happen  rriainly  because  a 
detail  of  a  process  has  been  overlooked.  Repairmen,  as  a  general  rule, 
are  quite  sure  of  their  materials  and  major  methods.  However,  if 
they  are  kept  busy  with  customers  as  well  as  doing  the  actual  work 


528 


Automotive  Trade  Training 


in  the  shop  and  are  called  frequent- 
ly from  their  work,  the  repair  work 
is  bound  to  suffer.  Repairing  re- 
quires careful  supervision.  The 
master  repairman  who  is  required  to 
take  care  of  customers  should  have 
an  assistant  well  trained  to  do  this 
supervising. 

1.  Cement,  if  not  allowed  to 
dry  thoroughly,  causes  a  porous 
condition  between  new  and  the  old 
material.  This  condition  will  show 
up  black  and  glossy.  The  pores  will 
be  small. 

2.  Cement,  if  allowed  to  dry 
too  long,  loses  its  adhesive  proper- 
ties, thus  permitting  separation. 
This  condition  can  properly  be 
called  "air  cure"  because  the  air 
attacks  the  cement,  causing  one 
form  of  cure. 

3.  If  dust  is  allowed  to  settle 
on  the  repair  before  it  is  completed 
and  it  is  riot  removed,  it  permits 
separation  after  the  cure,  because 
the  plies  of  raw  materials  do  not 
adhere  to  each  other. 

4.  Oil  or  grease  may  be  in 
either  the  old  tread  or  the  casing  as 
well  as  in  the  solvent  or  gasoline. 
This  is  caused  by  the  tire  standing 
in  pools  of  oil  or  by  running  on 
oiled  roads,  especially  when  the 
tread  is  badly  cut.  This  allows  the 
oil  to  soak  through  and  penetrate  to 
the  fabric  in  the  carcass. 

5.  Lack  of  pressure  in  a  cure 
also  causes  a  porous  condition.  In 
most  cases  it  can  be  detected  by 
poor  flow  of  the  raw  material.  It  is 
caused  by  leaky  sectional  airbags, 
poor    bead    molds    or    bad    clamps 

or  from  sectional  airbags  not  fitting  the  inside  of  the  casing  properly. 

6.     Buckles  inside  the  casing,  and  cracks  on  the  outside  of  the 

casing  along  the  tread  line  in  sectional  repairs  are  usually  caused 


Fig.  627.     Semi-Cured   Tread  Bands. 


Tire  Care  and  Vulcanizing  529 

by  too  much  pressure  exerted  on  clamps  in  placing  the  casing  in  the 
cavity  of  the  mold.     The  mold  cavity  is  then  smaller  than  the  casing. 

7.  Clamps  properly  fitted  should  be  just  tight  enough  to  form 
a  complete  mold  around  the  casing. 

8.  Do  not  handle  repair  material  any  more  than  can  possibly 
be  helped. 

9.  In  washing  a  repair  with  solvent  the  rag  should  be  slightly 
moistened  and  not  saturated. 

10.  Occasionally  it  is  found  that  after  curing  a  casing,  the  first 
layer  of  fabric  bulges  and  upon  opening  it  with  an  awl  gas  comes  out. 
This  condition  is  usually  caused  by  a  deteriorated  condition  of  the 
carcass. 

SUGGESTIONS   FOR  HANDLING  REPAIR  MATERIALS 

1.  Raw  gum  and  fabric  should  be  kept  in  a  cool,  dry  place. 

2.  If  possible,  the  stock  room  should  be  dark.  It  is  imperative 
that  the  raw  stock  should  not  be  near  an  open  window  nor  in  a  direct 
draft  or  sunlight.  Dampness  should  be  avoided.  Raw  stock  should 
never  be  allowed  to  stand  on  the  floor  or  on  a  table.  Wherever  pos- 
sible, they  should  be  placed  on  a  rack  with  a  rod  running  through  the 
shell  on  which  the  material  is  rolled. 

3.  In  warm  weather  raw  gums  will  sag  from  their  own  weight, 
even  when  tightly  rolled  on  the  holland.  To  overcome  this,  it  is 
advisable  to  turn  the  stock  at  frequent  intervals. 

4.  Repair  gums  and  fabric  received  in  cold  weather  sometimes 
appear  hard  and  lifeless.  They  are  merely  frozen.  Freezing  does  not 
affect  the  stock.  If  received  in  this  condition  it  should  be  put  in  a 
warm  room  a  short  time  to  thaw  out. 

5.  In  order  to  get  good  results  from  a  repair  it  is  essential  that 
the  stock  be  perfectly  clean  when  used. 

6.  Dirt  and  bloom,  or  free  sulphur,  always  collect  on  uncured 
rubber.  If  this  is  not  thoroughly  washed  oflf  with  gasoline  before 
used  in  a  repair,  an  imperfect  union  will  surely  result. 

7.  Gums  and  fabrics  that  have  bloomed  sometimes  appear  old 
and  do  not  appear  to  be  in  condition  to  be  used.  If  the  bloom  and 
dirt  are  washed  off  with  solvent,  the  gum  will  give  good  results. 

8.  The  quality  of  gums  or  fabric  is  not  necessarily  determined 
by  the  length  of  time  before  they  start  to  bloom.  All  uncured  gums 
are  bound  to  bloom  eventually. 

9.  Always  save  your  scrap  gums.  They  can  be  returned  for 
credit.  The  value  of  this  material  when  returned  depends  largely 
upon  its  condition.  The  gums  should  be  kept  separate  and  free  from 
foreign  materials. 


630  Automotive  Trade  Training 

10.  All  repair  fabrics  should  be  cut  on  the  bias  at  an  angle  of 
45  degress.  A  repair  made  of  fabric  cut  on  the  straight  becomes  hard 
and  often  bulges. 

11.  Tread  stock  dissolved  in  gasoline  or  solvent  does  not  make 
a  good  vulcanizing  cement.     It  is  also  costly. 

12.  The  most  economical  plan  to  make  cement  is  to  buy  good 
grade  cement  gum. 

13.  Make  test  cures  of  your  rav^  gum  and  fabric  at  least  once 
a  week. 

14.  For  testing  open  heat  and  sectional  repair  work,  build  up  a 
section  on  an  old  tire  and  cure  in  the  usual  manner.  Cut  from  this 
cured  section  a  piece  about  an  inch  wide  and  separate  the  different 
stocks  wherever  there  should  be  a  union. 

15.  By  pulling  these  slowly,  it  is  easy  to  see  whether  you  are 
getting  good  strong  unions  in  your  cure.  You  can  also  judge  as  to 
the  cure  by  the  condition  of  the  stock. 

16.  A  good  method  of  testing  rubber  for  cure  is  to  cut  a  narrow 
strip  about  3^"  wide  in  the  edge  of  the  piece  to  be  tested.  By  pulling 
this,  the  elasticity  and  "set"  can  be  determined.  A  well  cured  stock 
should  be  elastic  and  lively,  and  the  strip  should  return  to  very  nearly 
its  original  length. 

17.  When  raw  gums  do  not  flow,  it  is  a  pretty  sure  sign  of  in- 
sufficient pressure  on  the  inside  of  the  casing. 

18.  Always  inflate  sectional  airbags  to  70  pounds  pressure.  If 
the  bag  or  coil  is  not  large  enough  to  fill  out  the  casing  properly  it 
should  be  padded  with  strips  of  old  fabric  until  it  fits  snugly. 

19.  Be  sure  that  the  fabric  in  the  casing  to  be  repaired  is  dry 
before  you  proceed  with  a  repair.  Fabric  separation  will  result  from 
failure  to  heed  this  warning.  An  inside  patch  vulcanizer  serves  as 
an  excellent  drier.  Temperature  should  not  exceed  150  degrees  F. 
in  drying. 

20.  If  extensive  repairs  are  made  on  casings  with  separated 
fabric,  the  heat  during  the  cure  will  expand  the  air  between  the  plies 
and  increase  the  separation. 

21.  When  cutting  rubber,  dip  your  knife  in  water.  It  lessens 
the  resistance. 

22.  The  best  way  to  repair  a  leaky  splice  is  to  insert  a  new 
section. 

23.  The  life  of  an  airbag  can  be  greatly  prolonged  if  the  bag  is 
handled  properly. 

24.  Do  not  use  an  airbag  as  a  building  form. 

25.  Do  not  remove  the  air  bag  from  the  casing  by  pulling  it 
by  the  stem. 

26.  When  the  tire  has  been  placed  in  the  mold,  do  not  fasten 


Tire  Care  and  Vulcanizing  531 

the  clamps  down  securely  until  after  the  airbag  has  been  partially 
inflated. 

27.     Always  dust  the  airbag  slightly  with  soapstone  before  using. 

28:  When  in  use  keep  the  sectional  airbag  inflated  to  70  pounds 
pressure. 

29.  If  a  bag  becomes  porous,  it  can  be  repaired  by  forcing  a 
small  quantity  of  C-15  vulcanizing  cement  through  the  stem  and  into 
the  bag. 

30.  Here  is  the  method  to  use  in  doing  this. 

31.  After  removing  the  valve  inside,  clasp  the  bag  between  your 
hands,  and  exhaust  as  much  of  the  air  in  the  bag  as  possible. 

32.  Place  the  stem  of  the  bag  in  the  cement  and  release  the 
pressure  gradually  until  a  small  quantity  of  cement  has  been  drawn 
in.  Then  roll  the  bag  around  so  as  to  get  the  cement  distributed 
over  the  inside.     Allow  the  cement  to  dry. 

33.  Repeat  the  operation  three  times  (using  in  all  about  one- 
fourth  pint  of  cement).     The  bag  is  now  ready  for  use. 

34.  When  a  tube  splice  is  made  by  the  acid  cure  process  and  it 
does  not  hold,  it  can  usually  be  traced  to  one  of  the  four  following 
causes : 

35.  The  cement  was  not  dry. 

36.  The  acid  was  too  weak. 

Z7 .  The  splice  was  not  made  quickly  enough  after  the  acid  was 
applied. 

38.  There  was  insufficient  pressure  on  the  splice  after  the  union 
was  made. 

39.  After  an  inner  tube  has  been  repaired,  always  test  it  in  water 
to  make  sure  that  there  is  not  another  leak. 

PRACTICAL  VULCANIZING  HINTS 

1.  Undercuring  of  sectional  repairs  can  often  be  traced  to  the 
molds.  '  If  the  molds  are  clogged  with  dirt,  or  if  air  pockets  are  allowed 
to  form  in  the  molds,  it  takes  longer  to  heat  them  and  consequently, 
longer  to  cure  the  repairs. 

2.  Water  collects  in  the  molds  occasionally,  stopping  circulation, 
with  the  result  that,  while  the  pressure  may  be  correct,  the  tempera- 
ture of  the  molds  will  be  too  low  to  accomplish  the  cure  in  the  pre- 
scribed time. 

3.  At  least  once  a  month  the  steam  pipe  should  be  disconnected 
and  a  strong  current  of  compressed  air  should  be  blown  through  the 
molds. 

4.  A  surprising  amount  of  dirt  and  water  will  be  dislodged  by 
this  process. 

5.  There  will  be  comparatively  little  trouble  from  this  source 
if  your  molds  have  a  drain  at  the  lowest  point,  where  water  is  likely 


532  Automotive  Trade  Training 

to  collect,  and  a  pet  cock  at  the  highest  point  to  allow  trapped  air  to 
escape. 

6.  An  airbag  that  has  been  used  in  several  cures  becomes 
elongated  and  may  extend  beyond  the  ends  of  the  sectional  mold. 
This  causes  a  ridge  on  the  tire  at  the  ends  of  the  mold.  To  prevent 
this,  bevel  the  edges  of  the  mold  back  about  half  an  inch. 

7.  Small  cuts  and  fabric  breaks  in  motorcycle  tires  can  be 
repaired  on  the  tube  plate. 

8.  It  is  very  important  to  know^  the  relative  degrees  of  tempera- 
ture to  pounds  of  steam  pressure.  The  foUov^ing  table  gives  this 
information : 

Pounds  Steam  Pounds  Steam 

Temperature  F  Pressure         Temperature  F.        Pressure 

227.2  5  280.6  35 

239.4  10  286.7  40 

249.8  15  292.4  45 

258.8  20  297.7  50 

266.8  25  302.6  55 

274.0  30  307.2  60 

This  table  w^ill  not  hold  true  in  extreme  altitudes  or  climates. 
In  such  cases  it  is  v^ell  to  revise  the  table  with  the  use  of  a  ther- 
mometer so  that  you  can-  be  sure  of  getting  the  required  temperature^ 
with  the  designated  steam  pressure. 

9.  All  metal  surfaces  that  come  in  contact  with  the  raw  gum 
during  the  cure  should  be  kept  highly  polished  and  perfectly  clean. 

10.  Clean  your  molds  or  cores  as  follows: 

First,  polish  with  fine  emery  paper  or  wire  cloth.  Then  apply  a 
solution  of  soap  and  water,  or  soft  soap  by  means  of  a  large  paint 
brush. 

11.  In  making  cement,  take  a  quantity  of  raw  gum  and  cut  it  up 
in  small  pieces.  Then  place  in  a  can  together  with  a  small  quantity 
of  high  test  gasoline  and  stir  every  hour  or  two  until  the  gum  has 
dissolved  to  the  consistency  of  cream. 

12.  Cement  should  be  thoroughly  stirred  each  time  it  is  used  or 
the  results  are  bound  to  be  variable,  due  to  the  settling  out  of  curing 
agents.     Cement  is  like  paint  in  this  respect. 

13.  C-15  Cement,  when  ready  for  use  should  be  of  a  consistency 
similar  to  that  of  cream  or  house  paint.     It  should  flow  readily. 

14.  If  C-15  Cement  is  found  very  heavy  when  purchased,  or  if  it 
becomes  very  thick,  it  may  be  thinned  with  a  good  grade  of  gasoline 
(one  that  shows  no  oil  residue)  or  benzol. 

15.  Where  several  gallons  of  cement  are  required  daily,  a  small 
barrel  or  churn  can  be  used  to  advantage  for  mixing. 

16.  During  the  time  that  C-15  Cement  is  being  used,  it  should 


Tire  Care  and  Vulcanizing 


533 


be  stirred  frequently.     Poor  results  will  be  obtained  unless  this  is 
done. 

17.  Never  hang  cemented  tires  in  a  draft  or  over  vulcanizers  to 
hasten  the  drying.  Allow  the  drying  process  to  take  its  natural 
course. 

18.  Vulcanizing  Cement  can  be  thinned  by  the  use  of  a  good 
rubber  solvent. 

19.  Gasoline  that  will  not  leave  a  grease  spot  on  white  paper 
after  it  has  been  allowed  to  evaporate  is  a  good  solvent. 


Fig.  628.     Akron-Williams  Vulcanizing  Kettle. 

20.  Benzine  or  energine  are  both  good  solvents  and  can  be  relied 
upon. 

21.  Grain  or  wood  alcohol  is  not  a  rubber  solvent  and  should 
never  be  used.  The  cement  may  appear  thinner  but  it  is  of  poorer 
quality.  Instead  of  acting  as  a  solvent  it  causes  coagulation  of  the 
rubber  particles. 

22.  So-called  "high  grade"  or  "more  power"  gasolines  contain 
substances  which  make  them  unfit  for  use  with  rubber  cement. 

23.  Low  gravity  solvents  contain  greasy  residues  which  are  de- 
trimental to  cement. 

24.  Solvent  should  be  added  a  little  at  a  time  and  then  stirred 
thoroughly  before  any  more  is  added. 


534 


Automotive  Trade  Training 


Tire  Care  and  Vulcanizing 


535 


25.  Cement  should  be  kept  in  covered  containers  when  not  in 
use. 

26.  Whenever  possible  cement  should  be  stored  in  a  cool,  dry- 
room  to  prevent  evaporation  of  the  solvent. 

VULCANIZATION 

Vulcanization  so  changes  the  physical  properties  of  rubber  as  to 
render  it  less  plastic  and  more  resistant  to  wear  and  mechanical 
strains.  Vulcanized  rubber  is  a  product  resulting  from  the  chemical 
union  of  crude  rubber  and  sulphur,  and  as  heat  accelerates  all  chemi- 


Fig.  G30.     Curing  on  hot  plate. 

cal  reactions  we  have  employed  the  aid  of  steam  to  bring  about  a 
quick  union  of  crude  rubber  and  sulphur. 

It  is  generally  known  that  other  chemicals  than  sulphur  are  also 
used  in  compounding.  These  chemicals  do  not  unite  with  the  rub- 
ber but  are  highly  dispersed  throughout  the  mass  and  their  presence 
gives  to  the  rubber  certain  desirable  properties  such  as  resistance  to 
wear  and  abrasion,  resiliency,  and  strength. 

Sulphur  and  rubber  combine  very  slowly  under  atmospheric  con- 
ditions and  this  is  what  we  call  spontaneous  cure.     It  takes  months 


536  Automotive  Trade  Training 

for  this  curing  to  materially  affect  the  physical  properties  of  the 
product,  so  we  find  this  matter  of  little  importance  to  the  average 
vulcanizer. 

Now,  according  to  certain  laws  of  chemistry,  an  excess  of  any 
element  entering  into  a  chemical  combination  greatly  accelerates  the 
speed  of  reaction.  It  is  for  this  reason  that  it  is  necessary  to  use  an 
excess  amount  of  sulphur.  However,  this  excess,  unless  it  is  too 
great,  does  not  in  any  way  affect  the  physical  properties  of  the  vul- 
canized rubber.  Rubber  blooming  is  nothing  but  the  excess  of  sul- 
phur in  the  vulcanized  rubber  working  to  the  surface. 

It  is  also  true  that  some  of  this  excess  sulphur  never  blooms,  and 
as  rubber  ages  there  is  a  slow  process  of  spontaneous  vulcanization 
going  on  which  is  called  "aftercure".  It  is  for  this  reason  that  rubber 
when  very  old  becomes  hard  and  lifeless  and  has  a  tendency  to  chip 
easily. 

Well  made  repair  materials  are  compounded  with  the  correct 
amount  of  ingredients  so  that  when  properly  cured  the  effect  of 
"after  cure"  is  reduced  to  a  minimum.  For  the  above  reasons,  to 
get  good  results  it  is  absolutely  necessary  to  use  the  temperatures 
and  time  recommended  for  curing  the  different  repairs. 

Cures. — Following  cures  are  recommended  for  curing  passenger 
car  tire  and  tube  repairs: 

Tube  Repairs. — The  length  of  time  necessary  to  cure  a  repair 
depends  on  its  thickness.  G-180,  cured  in  thin  sheets,  cures  in  five 
minutes  at  60  pounds  steam  pressure.  However,  when  built  up  in 
repairs,  a  somewhat  longer  time  must  be  allowed  in  order  that  the 
heat  may  penetrate  and  give  a  good  cure  throughout. 
On  Tube  Plate  at  60  lbs.  Steam  Pressure: 

G-180  alone,  five  to  eight  minutes. 

G-180  with  G-190  reinforcement,  ten  to  twelve  minutes,  depend- 
ing on  the  thickness  used. 
On  Tube  Plates  at  40  lbs.  Steam  Pressure: 

G-180  alone,  ten  to  fifteen  minutes. 

G-180  with  G-190  reinforcement,  eighteen  to  twenty-five  minutes, 
depending  on  the  thickness  used. 

Valve  Patch  with  C-25  Cement.     Cure  12  minutes  at  40  lbs.     Sec- 
tional Work  (Built  up  as  Described)  : 

For  full  section  and  half  section  and  quarter  section. 

For  Smooth  Tread: 

3",  3>4" 55  minutes  at  40  pounds 

4" 60  minutes  at  40  pounds 

41^" 65  minutes  at  40  pounds 

5" 70  minutes  at  40  pounds 

Note :  Add  twenty  minutes  to  time  of  cure  when  negative  pad  is 
used  to  preserve  the  tread  pattern.     Add  fifteen  minutes  to  time  of 


Tire  Care  and  Vulcanizing  537 

cure  when  soapstone  and  jacket  are  used  to  preserve  tread  pattern. 
In  curing  a  quarter  section  the  additional  time  allowance  for  matrix 
or  soapstone  need  not  be  added  to  the  cure. 

Cure  full  section  built  in  tire  which  has  tread  cut  off  for  retread- 
ing: 

3'\  3y2" 25  minutes  at  40  pounds 

4",  4>^",  5" 30  minutes  at  40  pounds 

Top  Section:     In  sectional  mold  (2  plies  stepped  out). 

For  Smooth  Tread: 

3",  3^" 50  minutes  at  40  pounds 

4",  4^" 55  minutes  at  40  pounds 

5" 60  minutes  at  40  pounds 

Note :  Allow  fifteen  minutes  additional  time  when  soapstone  and 
jacket  are  used  to  preserve  the  tread ;  twenty  minutes  when  matrix 
is  used. 

When  top  section  is  built  in  retread  cure  in  regular  manner. 
Side  wall  Cuts: 

Cure  on  hot  plate  or  in  sectional  mold  50  minutes  at  40  pounds 
when  no  plies  have  been  cut  out. 

When  outer  ply  has  been  stepped  out,  cure  as  recommended  for 
quarter  section. 

When  strengthening  plies  are  put  inside  tire,  cure  same  as  retread 
in  kettle. 
Cure  for  Negative  Pad  or  Matrix: 

20  minutes  at  40  pounds  in  sectional  mold. 
Tread  Repairs : 

Cure  45  minutes  for  cuts  about  ys"  deep ;  60  minutes  for  cuts 
about  ^ "  deep. 
Retread  with  All- Weather  or  Rib  Tread  Band: 

3",  3^^",  4" 50  minutes  at  40  pounds 

43^",  5" 55  minutes  at  40  pounds 

In  retreading  kettle. 
One-Third  Circle  Retreading: 

Cure  at  40  pounds  steam  pressure: 

No.  1  Camel  back,  3",  3^" — 55  minutes  at  40  pounds  steam 
pressure. 

No.  2  Camel  back,  4",  4^" — 60  minutes  at  40  pounds  steam 
pressure. 

No.  3  Camel  back,  5" — 70  minutes  a.\  40  pounds  steam  pressure. 

Cure  at  50  pounds  steam  pressure : 

No.  1  Camel  Back,  3",  3}^" — 45  minutes  at  50  pounds  steam 
pressure. 

No.  2  Camel  back,  4",  4'^" — 50  minutes  at  50  pounds  steam 
pressure. 

No.  3  Camel  back,  5" — 60  minutes  at  50  pounds  steam  pressure. 


638 


Automotive  Trade  Training 


JOB  202.     REPAIRING  PIN   HOLES  AND  SMALL  PUNCTURES. 

1.  "Pick  out"  puncture  to  a  small  open  injury. 

2.  Buff    with    emery    cloth — stretch    tube    so    that    injury    can    be    buffed 
thoroughly. 

3.  Wash  with  solvent  to  remove  dust. 

4.  Apply  two  coats  of  C-25  quick  cure  cement  overlapping  the  injury. 

5.  Then  "drive"  small  "thread"  of  G-180  tube  gum  through  injury  so  that 
it  will  form  a  rivet  head  on  inside  of  tube. 

6.  Fill  up  injury  flush  with  outside  surface  of  tube — do  not  overlap  on 
the  outside. 

7.  Cure  according  to  chart. 

8.  It  is  always  well  to  use  a  piece  of  holland  on  the  tube  plate. 


Fig.  631.     Correct  method  of  stitching  in  gum. 

JOB    203.     REPAIRING    LARGE    INJURIES    AND    BLOW    OUTS    IN 

TUBES. 

1.  Ragged  edges  of  injury  should  be  trimmed  and  thoroughly  buffed. 

2.  Buff  the  side  of  the  injury  and  the  inside  of  the  tube  for  a  distance  of 
1''  around  this  injury.     Wash  this  surface  with  a  rag  moistened  with  solvent. 

3.  Apply  both  inside  for  a  distance  of  l"  around  the  break  and  to  the 
edges  of  the  break  two  coats  of  C-25  quick  cure  cement. 

4.  Cut  a  piece  of  G-190  cured  back  tube  gum  with  rounded  corners,  ^'^ 
larger  than  the  injury.  Insert  on  inside  of  injury  with  raw  gum  side  next  to 
the  tube. 

5.  This  inside  reinforcement  patch  can  be  inserted  by  holding  the  patch 
with  a  pair  of  long-nosed  pliers.  Dip  it  in  solvent  and  insert  it  before  the 
solvent  dries.  When  this  is  done,  care  should  be  taken  to  hold  the  reinforcing 
patch  away  from  the  tube  on  the  inside,  in  order  to  allow  the  solvent  to 
evaporate  before  stitching  down  the  patch. 

6.  Fill  up  the  injury,  on  outside,  with  G-180  tube  gum,  flush  with  the 
outside  surface  of  the  tube.    Do  not  overlap  at  edges.    This  should  not  be 


Tire  Care  and  Vulcanizing 


639 


filled  in  until  the  reinforcing  patch  has  been  allowed  to  dry  for  at  least  ten 
minutes. 

7.     Cure  on  tube  plate,  according  to  chart. 


Fig.   632.     Injury   trimmed   out   ready   for   repair. 

JOB  204.     SPLICING  INNER  TUBES. 

1.  New  section  inserted  in'  the  tube  should  be  5"  longer  than  the  old 
section  cut  out,  thus  allowing  2^/^"  for  the  splice  at  each  end. 

2.  The  edges  should  be  beveled  to  feather  edge  at  an  angle  of  approxi- 
mately 40  degrees. 

3.  One  edge  should  be  beveled  from  the  outside  and  the  other  edge  from 
the  inside. 

4.  The  edges  of  the  inner  tube  itself  should  be  beveled  in  the  same 
manner  as  the  section  to  be  inserted. 

5.  Both  tube  and  section  should  be  buffed  with  emery  cloth  or  wire 
buffer,  3"  from  each  end.  One  end  of  the  tube  and  section  should  be  buffed  on 
the  outside  and  the  other  end  on  the  inside.  To  facilitate  buffing  the  tube  may 
be  put  on  a  mandrel, 

6.  One  end  of  the  section  should  be  lapped  back  2^/^"  on  the  female  tube 
mandrel. 

7.  The  end  of  the  tube  itself  should  be  lapped  back  5"  and  then  folded 
back  on  itself  2%"  on  the  male  tube  mandrel. 

8.  Apply  two  coats  of  C-35  acid  cure  cement. 

9.  Allow  the  first  coat  to  dry  twenty  minutes;  second  coat,  thirty 
minutes. 

10.  The  two  ends  are  then  placed  in  position  and  acid  or  curing  solution 
is  applied, 


540 


Automotive  Trade  Training 


Fig.  633.     Inserting  inside  reinforcement. 

11.  The  lap  on  the  female   mandrel  should  be  pushed  quickly  over  the 
male  mandrel  and  tightly  wrapped  with  strips  of  rubber  or  cloth. 

12.  Allow  the  splice  to  be  wrapped  for  approximately  thirty  minutes. 


Fig.  63i.     Filling  up  injury  on  the  outside. 


Tire  Care  and  Vulcanizing 


541 


13.  It  is  always  well  to  slide  the  female  mandrel  forward  so  that  1%"  of 
tube  remains  after  cementing.  This  eliminates  the  possibility  of  an  overlap 
at  splice. 

14.  After  applying  acid  or  curing  solution,  the  ends  should  be  placed 
together  and  wrapped  in  less  than  eight  seconds  to  insure  perfect  results. 

ACID  CURING  SOLUTION. 

Acid  curing  solution  may  be  secured  from  the  druggists  or  from  the  drug 
supply  houses.     The  formula  for  this  solution  is  given  below: 


Fig.   635.     Tube   on   mandrel   ready   to   splice. 

1.7  fluid  oz.  Sulphur  monochloride  (S  Cl)  to  1  gal.  Carbon  tetra-chloride 
(CCl). 

It  is  possible  to  vulcanize  a  splice  on  the  tube  plate.  Those  desiring  to 
use  this  method  should  follow  directions  given  in  Job  305. 

JOB  205.     VULCANIZED  TUBE  SPLICE. 

1.  Cut  out  the  bad  section  of  the  tube  to  be  spliced. 

2.  From  another  tube  of  good  rubber  cut  a  section  5"  longer  than  the  one 
removed.     This  permits  of  a  splice  at  each  end  of  2^/4". 

3.  Turn  back  the  ends  of  the  section  or  tube.  Roughen  edges  of  both 
section  and  tube  2^"  from  the  ends.     Clean  with  gasoline. 


Fig.  636.     Tube   spliced  and  wrapped. 


542 


Automotive  Trade  Training 


4.  Cement  with  vulcanizing  cement,  two  coats.  The  first  coat  should 
dry  20  to  30  minutes,  then  apply  the  second  coat  and  let  dry  two  or  three 
hours. 

5.  Place  about  a  tablespoonful  of  French  talcum  in  the  tube.  This  is 
used  to  dust  the  inside  of  the  splice  to  prevent  the  edges  from  sticking 
together  when  vulcanizing. 

6.  With  the  talcum  in  the  tube  the  ends  may  be  evened  up  and  the  ones 
which  have  been  turned  back  may  be  pulled  over  the  other  ends.  Splicing 
mandrels  may  be  used  here  if  desired. 

7.  Secure  two  blocks  of  wood  V^"  narrower  than  the  tube,  but  longer 
than  the  splice.  Place  one  of  these  over  each  splice.  It  will  take  three  cures 
of  fifteen  minutes  each  to  finish  the  repair. 

8.  When  cured  inflate  the  tube  after  which  the  rough  edges  of  the  splice 
may  be  bufied  off  on  the  buffing  wheel. 

JOB  206.     COLD  PATCHING. 

This  method  of  repairing  tubes  is  not  to  be  recommended  for  greneral  use. 
It  is  well,  however,  for  the   student  to  familiarize   himself  with   the  process. 


Fig.  637.     Stitching  down  valve  patch. 

The  success  of  the  work  depends  to  a  large  extent  on  the  proper  roughing  or 
sandpapering  of  the  rubber  to  be  joined.  Always  allow  sufficient  time  for  the 
cement  to  dry  properly  before  assembling  the  patch  on  the  tube.  Patching 
cement  is,  at  times,  also  used  for  applying  reliners. 

1.  Find  the  leak.     Roughen  with  sandpaper  or  rasp. 

2,  Clean  with  gasoline,  and  cement  with  patching  cement. 


Tire  Care  and  Vulcanizing  643 

3.  Secure  a  patch  or  piece  of  cured  rubber.     Prepare  same  as  the  tube. 

4.  Permit  cement  to  dry  from  ten  to  fifteen  minutes. 

5.  Place  the  patch  over  the  injury  and  rub  down  good  and  firm. 

6.  In  the  case  of  a  road  repair  the  tube  may  be  put  into  immediate  use. 

JOB  207.  APPLYING  VALVE  PATCHES  OR  PADS. 

The  best  method  of  repairing  breaks  in  valve  patches  at  the  point  where 
the  valve  stem  comes  through  is  to  apply  a  new  patch  to  the  tube  as  described 
below.  .  Take  all  fittings  off  the  valve  and  force  valve  back  into  tube.  A  hole 
is  cut  through  the  tube  at  the  point  where  the  patch  was  applied  and  the  valve 
stem  put  in.  The  old  valve  patch  is  then  repaired  by  filling  the  hole  as 
described  for  large  injuries  and  curing. 

1.  Buff,  with  emery  cloth,  surface  of  tube  to  which  patch  is  to  be  applied. 

2.  Wash  with  solvent. 

3.  Apply  two  coats  of  C-35  acid  cure  cement. 

4.  First  coat  should  be  allowed  to  dry  twenty  minutes;  second  coat,  thirty- 
minutes. 

5.  Apply  acid  solution  to  cemented  portion  of  tube  and  immediately  place 
patch  in  position. 

6.  Stitch  patch  down  thoroughly,  being  careful  to  secure  the  edges. 

7.  Then  wrap  on  the  tire  last  or  tube  mandrel  with  strips  of  cloth  and 
leave  it  in  this  position  for  thirty  minutes. 

8.  Another  method  of  applying  patches  is  to  apply  C-25  quick  cure 
vulcanizing  cement  in  place  of  C-35  and  curing  on  hot  plate. 

JOB  208.     REPLACING  VALVE  STEMS. 

1.  Around  the  base  of  the  valve  is  a  fabric  reinforcement  in  the  tube. 
Consequently  the  valve  cannot  be  pulled  out  without  rupturing  the  fabric. 

2.  To  replace  the  valve  stem,  cut  a  hole  in  the  tube  large  enough  to 
remove  the  old  valve  stem,  and  insert  the  new  one  through  it.  After  the  new 
valve  s«tem  is  inserted,  repair  this  hole  in  the  usual,  manner, 

JOB  209.    OUTER  CASING  REPAIRS. 

General  Rules  for  the  Preparation  of  Fabric  Tires. — Punctures  and  small 
holes  through  the  tires,  and  small  fabric  breaks  can  be  repaired  by  the  appli- 
cation of  a  built-up  sectional  reliner.  The  size  and  number  of  plies  in  this 
reliner  depends  upon  the  size  of  the  tire  and  upon  the  condition  of  the  plies. 

Four  types  of  sections  are  used  in  the  repair  of  large  breaks  in  fabric  tires. 
They  are:  quarter  section,  half  section,  full  section,  and  inside  section.  A 
top  section  is  used,  but  it  will  be  taken  up  under  the  heading,  "Tread  Cuts  and 
Retreading." 

The  inside  of  the  tire  should  be  buffed  thoroughly  before  the  repair  is 
torn  down.  After  the  carcass  plies  are  stepped  out  the  tire  will  be  too  flimsy 
to  allow  it  to  be  buffed  properly. 

The  length  of  the  section  is  determined  by  the  following  general  rules, 
which  apply  to  all  types  of  sections. 

1.  All  plies  are  stepped  down  l"  in  the  direction  around  the  tire. 

2.  Two  plies  are  removed  in  the  case  of  3",  3^/^",  and  4"  tires;  and  three 
plies  in  the  4%"  and  5"  tires,  unless  the  size  of  the  injury  warrants  a  stronger 
repair,  this  is,  to  a  large  extent,  a  matter  of  judgment. 

3.  A  margin  of  1^/^"  is  left  between  the  last  ply  removed  and  the  extreme 
point  of  injury. 

4.  The  tread  is  laid  back  1^/^"  further  than  the  first  ply  removed. 


544 


Automotive  Trade  Training 


Fig.  RSS.     Diagram  of  quarter  section. 

JOB  210.     TEARING  DOWN  QUARTER  SECTION. 

A  quarter  section  is  used  in  the  case  of  a  tire  being  rim  cut  or  with  a 
broken  bead,  in  3",  3^",  and  4"  regular  clincher  casings.  The  length  of  the 
section  is  determined  by  the  rules  given  above.  It  is  necessary  to  remove- 
only  two  plies  of  old  fabric. 

In  the  case  of  a  quarter  section,  the  side  wall  is  removed  4"  from  the 
extreme  points  of  injury.  The  ends  are  skived. .  The  chafing  strip  is  removed 
^"  inside  the  point  at  which  the  side  wall  was  removed.  Remove  the  top  ply, 
cutting  2^/^"  outside  of  the  extreme  points  of  the  injury  and  %"  below  the 
tread  line.  Take  this  ply  out  to  the  toe  of  the  bead.  Remove  the  second  ply, 
stepping  down  l''  on  the  ends  and  Yi"  on  the  tread  side.  It  is  also  removed 
to  the  toe  of  the  bead.  Skive  the  edges  of  the  injury,  removing  all  loose  fabric. 
After  repair  is  ready  to  buff,  the  ends  of  the  injury  should  not  touch,  and 
should  taper  to  a  feather  edge.  Buff  thoroughly  all  the  exposed  outside 
surface  \"  farther  than  the  longest  ply  stepped  out,  and  from  the  toe  of  the 
bead  to  the  center  of  the  tread.     It  is  now  ready  to  cement. 

Clean  with  cloth  moistened  with  solvent.  Apply  three  coats  of  C-16  or 
C-15  cement  as  per  the  following  directions  for  the  application  of  cement. 
These  directions  are  general  and  are  to  be  followed  in  the  cementing  of  all 
types  of  repairs: 

1.  Apply  the  first  coat  thin  and  rub  in  well.  This  corresponds  to  the 
filler  coat  in  painting. 

2.  Apply  the  second  coat  heavier  than  the  first  and  smoothly.  This  is  a 
cover  coat. 

3.  Apply  the  third  and  last  coat  thinner  than  the  second  and  heavier  than 
the  first,  and  rub  in  well.     This  is  a  finish  coat. 

4.  Allow  the  first  coat  to  dry  from  30  to  60  minutes,  the  second  30  to  60 
minutes,  and  the  last  until  the  cement  becomes  tacky,  which  occurs  in  three  to 
five  hours,  depending  upon  the  humidity.  Cement  is  not  dry  until  all  of  the 
solvent  has  been  evaporated.  It  is  important  that  cement  should  not  be 
allowed  to  dry  too  long, .  otherwise  an  air-cured  film  will  form  which  may 
weaken  the  union. 


JOB  211.     BUILDING  UP  THE  QUARTER  SECTION. 

1.  Dust  and  dirt  should  be  removed  with  a  cloth  moistened  in  solvent. 
All  edges  of  the  old  fabric  should  be  covered  with  strips  of  G-170  ^"  wide. 
Fill  the  hole  through  the  tire  with  G-170  cushion  stock.  Apply  the  first  ply  of 
HF-41  frictioned  two  sides,  skim-coated  one  side,  with  the  skim  coated  side 
down,  lapping  Y^,"  over  the  old  fabric  and  extending  to  the  toe  of  the  bead. 


Tire  Care  and  Vulcanizing 


645 


Apply  the  second  ply,  lapping  ^"  over  the  old  fabric.  This  ply  is  made  long 
enough  to  extend  over  the  bead,  and  to  extend  up  the  inside  of  the  tire  to  a 
point  half  way  between  the  center  of  the  tread  and  the  tread  line. 

2.  Where  the  new  fabric  passes  over  the  bead,  it  should  be  trimmed  down 
to  make  a  butt  joint  with  the  old  fabric.  Replace  chafing  strip  with  LF-52, 
lapping  it  J4"  at  the  ends.     This  chafing  strip  will  extend  over  the  bead  and  l" 


Fig.  639.    Quarter  section  torn  down. 


inside  of  the  tire.  Replace  the  side  wall  with  G-lOO,  G-105,  or  G-115.  Before 
the  last  ply  is  stitched  down  on  the  inside  a  small  patch  of  HF-41,  1"  larger  all 
around  than  the  injury,  is  placed  over  it.  Cover  all  edges  of  the  new  fabric 
with  strips  of  G-170. 

3.     Dust  the  inside  and  the  outside  of  the  casing  lightly  with  soapstone. 
Repair  is  now  ready  to  be  cured  according  to  table. 


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Automotive  Trade  Training 


Fij^-.  040.     ;->Utclihiy  (K-wii   plies  in   (laarter  s^'ction. 

JOB  212.     TEARING  DOWN  FOR  HALF  SECTION. 

1.  A  half  section  is  built  into  the  tire  when  the  injury  is  between  the  bead 
and  the  center  of  the  tread.  The  length  of  the  section  is  determined  by  the 
general  rules.  It  is  necessary  to  remove  only  two  plies  of  old  fabric.  When 
the  injury  is  large  enough  to  warrant  the  removal  of  more  than  two  plies,  the 
full  section  must  be  built  into  the  tire. 

2.  Lift  the  tread  and  breaker  from  one  end,  allowing  the  tread  to  hinge  at 
the  other.  Remove  the  side  wall  4"  from  the  extreme  points  of  injury.  Skive 
the  edges.  The  chafing  strip  is  removed  Y^"  inside  the  point  at  which  the  side 
wall  was  removed.  Measure  back  XV^"  from  the  ends  of  the  section  and  step 
out  the  top  ply.  The  top  ply  is  stepped  out  1"  from  the  tread  line  on  the  side 
opposite  the  break  to  the  toe  of  the  bead  on  the  same  side  as  break.  The 
second  ply  is  taken  out  \"  narrower  all  around  than  the  first.  The  ends  of  the 
tread  at  the  point  where  it  is  cut  across  the  tire  should  be  skived  on  an  angle 
of  45°.     If  there  is  a  hole  through   the   tread,   all  loose   gum  is   trimmed  out. 


Fig.  641.     Inside  of  casing,   illustrating  plies  laid  back  to  show  construction. 


Tire  Care  and  Vulcanizing 


547 


The  exposed  surface  on  the  outside  of  the  tire  is  buffed.  The  inside  of  the 
tire  is  buffed  from  toe  to  toe  of  beads  and  l"  longer  on  either  end  than  the 
largest  ply  taken  off;  this  should  be  done  before  the  tire  is  torn  down.  Follow 
the  general  instructions  for  cementing. 

JOB  213.     BUILDING  UP  THE  HALF  SECTION. 

1.  When  the  cement  is  dry,  clean  it  with  a  cloth  moistened  with  solvent 
and  cover  the  outside  of  the  entire  exposed  surface  with  G-170,  1/64"  gauge. 
This  gauge  can  be  obtained  by  cutting  the  i^"  gauge  stock  one-half  the  size  of 
the  surface  to  be  covered  and  stretching  100%,  the  G-170  extending  to  within 
IJ/^"  of  the  heel  of  the  bead. 

2.  The  hole  through  the  tire  is  filled  with  G-170  cushion  gum, 

3.  The  first  ply  is  replaced,  lapping  the  edges  of  the  second  ply  removed 
^".  The  second  ply  is  replaced,  lapping  the  edges  of  the  first  ply  removed 
^".  This  ply  is  cut  long  enough  to  cover  the  inside  of  the  tire  from  bead  to 
bead.  At  the  point  where  the  fabric  goes  over  the  bead,  it  is  skived  so  as  to 
make  a  butt  joint  with  the  old  fabric.  After  this  ply  is  replaced,  cover  the 
entire  surface  of  the  tread  with  G-170,  3*2"  gauge.  The  chafing  strip  is  replaced, 
lapping  the  old 
G-105,  or  G-115. 

4.  The  tread  is  then  laid  down,  stitching  carefully  between  the  buttons. 
The  "V"-shaped  hole  where  the  tread  was  cut  is  filled  with  tread  stock  higher 
than  the  original  tread,  the  new  gum  is  then  cut  out  to  match  the  pattern  of 
the  tread.     Any  holes  in  the  tread  are  repaired  in  the  same  manner. 

5.  A  small  patch  of  HF-41  1"  larger  all  around  than  the  injury  is  placed 
over  it.  The  last  ply  from  the  outside  is  carried  over  the  bead  and  around  the 
inside  of  the  tire  to  within  l"  of  the  bead  on  the  side  opposite  the  injury. 

6.  The  chafing  strip  is  carried  l"  inside  the  tire.  Cover  all  raw  edges  of 
the  fabric  with  G-170.  Dust  the  inside  and  outside  of  the  tire  with  soapstone. 
The  tire  is  now  ready  to  be  cured  according  to  table. 


^^.x^^^^..-^ 

< 

•Bread 

x^ 

nr.. 

\V 

^ 

/^                 y^    \    ^ 

'\^ 

/  T 

\^\ 

/Bead 

Fig.  642.     Diagram  of  half  section. 

JOB  214.     TEARING  DOWN  FOR  FULL  SECTION. 

1.  A  full  section  is  used  in  the  case  of  a  large  blow-out  or  where  the 
blow-out  is  in  a  position  that  it  cannot  be  repaired  with  a  quarter  or  half 
section. 


548 


Automotive  Trade  Training 


2.  Two  plies  are  removed  from  the  3",  3^",  and  4"  tires,  and  three  from 
the  4%"  and  5"  tires.  This  is  a  general  rule  that  must  be  varied  if  the  injury- 
is  exceptionally  large  and  the  fabric  around  the  hole  must  be  removed  on 
account  of  separation.  The  length  of  the  section  is  determined  by  the  general 
rule. 

3.  The  inside  of  the  tire  should  be  buffed  2"  longer  than  the  longest  ply- 
removed. 


Fig.  643.     Half  Section  ready  to  be  built  up. 


4.  The  tread  is  laid  back  the  length  of  the  section  the  same  as  in  the  c.se 
of  a  half  section. 

5.  The  side  wall  is  removed  from  both  sides  of  the  tire,  and  both  chafing 
strips  are  removed.    The  first  ply  is  stepped  out  from  toe  of  bead  to  toe  of 


Tire  Care  and  Vulcanizing 


549 


bead,  and  1^"  inside  the  point  at  which  the  tread  was  laid  back.  The  other 
plies  are  stepped  out  l"  shorter  on  either  end  than  the  preceding.  All  loose 
fabric  and  all  loose  gum  is  trimmed  from  the  injury.  Buff  thoroughly  all  the 
exposed  outside  surface  of  the  carcass  and  underside  of  tread  and  cement 
according  to  general  instructions. 


Fig.  644.     Showing  method   of  laying  in  the  tread. 

JOB  215.     BUILDING  UP  THE  FULL  SECTION. 

1.  When  the  cement  is  dry,  remove  any  dust  with  a  cloth  moistened  with 
solvent.  Cover  the  exposed  surface  of  the  tire  with  G-170,  1/64"  gauge,  to 
within  1^"  of  the  bead.  Replace  the  old  plies  with  new  HF-41,  skim  coated 
side  down,  lapping  %'\  This  applies  to  the  underplies.  If  the  ply  taken  out 
is  trimmed  to  the  toe  of  the  bead,  the  ply  replaced  should  be  trimmed  at  the 
toe,  also;  thiat  is,  the  new  ply  should  be  trimmed  at  the  same  point  as  that  at 
which  the  old  ply  was  trimmed.  The  top  ply  is  cut  long  enough  to  cover  the 
outside  and  inside  of  the  carcass  and  to  lap,  itself  %".  The  side  walls  and 
chafing  strips  are  replaced  and  the  tread  is  laid  back  ill  the  same  manner  as  in 
the  half  section. 

2.  The  last  ply  is  then  stitched  over  the  bead.  On  the  one  side  it  is 
carried  1^/^"  up  the  inside  of  the  tire,  and  the  other  end  of  the  ply  carried 
around  the  inside  of  the  tire  to  meet  it  with  a  lap  of  H"-'.  At  the  point  where 
the  fabric  goes  over  the  bead,  it  is  skived  so  as  to  make  a  butt  joint  with  the 
old  fabric.  A  piece  of  new  fabric  is  cut  large  enough  to  run  from  toe  to  toe 
of  the  beads  and  extend  l"  further  on  either  end  than  the  ply  brought  around 
the  outside.     This  is   stitched  down  inside  the  tire  over  the  ply  which  was 


550 


Automotive  Trade  Training 


^< 

<=:S 

Tread 

Break 

^ 

r^ 

W 

/An 

\V 

,''^ 

/  ^/^ 

/        \W 

>s^ 

A 

A^^ 

\ 

>\- 

/yCBead 

Fig.  645.     Diagram  of  full  section. 


Fig.  64C.     Full  section  ready  for  building  up. 


Tire  Care  and  Vulcanizing  561 

brought  around  from  the  outside.  All  raw  edges  of  new  fabric  are  covered 
with  strips  of  G-170.  Dust  the  inside  and  outside  of  the  tire  lightly  with 
soapstone.     Cure  according  to  instructions. 

JOB  216.     INSIDE  SECTION. 

1.  Inside  sections  are  made  to  repair  fabric  breaks  on  the  inside  and 
almost  through  the  tire,  when  the  injury  is  small  and  it  is  deemed  inexpedient 
to  lift  the  tread.     It  is  not  used  to  make  repairs  below  the  tread  lines. 

2.  It  replaces  the  full  section  for  small  repairs.  Half,  or  less  than  half, 
of  the  plies  are  taken  out  in  four  or  five  ply  tires,  and  three  in  six  or  seven-ply 
tires.  When  two  plies  are  removed,  the  first  ply  is  taken  out  2J^"  from  the 
extreme  points  of  injury.  When  three  plies  are  removed,  the  first  ply  is  taken 
out  3^"  from  the  extreme  points.  The  largest  ply  is  taken  out  to  the  toe  of 
the  bead  and  each  ply  is  stepped  out  l"  narrower  than  the  first  ply.  This  is 
buffed  and  cemented  in  the  regular  manner. 


Fig.  647.     Photo  showing  inside  of  tire  and  method  of  carrying  ply  around  from  outside. 

3.  The  first  ply  is  replaced,  lapping  %''  all  around.  No  skim  coat  of  G-170 
is  necessary.  All  raw  edges  of  fabric  should  be  covered  with  a  narrow  strip  of 
G-170.  The  skim  coated  side  of  HF-41  is  placed  down.  All  underplies  are 
lapped  %".  The  last  ply  replaced  is  lapped  %"  and  carried  to  within  %"  of  the 
toe  of  the  bead.  One  or  two  over-all  plies  are  placed  over  the  repair  running 
from  toe  to  toe,  and  extending  1"  over  the  last  ply  replaced  in  the  tire.  Dust 
the  repair  with  soapstone  and  cure  according  to  instructions  for  full  section. 

JOB  217.     REPAIRING  OF  CORD  TIRES. 

The  Goodyear  Cord  Patch  is  used  when  the  cut  or  injury  in  the  cord  casing 
is  no  longer  than  3V^"  and  occurring  between  the  tread  lines. 

1.  Buff  the  inside  of  the  casing  from  toe  to  toe  of  bead  and  somewhat 
wider  than  the  patch  to  be  applied. 

2.  Trim  the  loose  gum  and  fabric  from  the  injury  so  that  the  edges  of  the 
plies  do  not  touch,  and  the  hole  is  free  and  open.  Taper  the  hole  so  that  the 
inside  is  larger  than  the  outside. 

3.  Buff  the  injury  thoroughly. 

4.  Clean  with  cloth  moistened  with  solvent. 

5.  Cement  outside  of  repair  to  be  made  with  C-15  or  C-16  vulcanizing 
cement. 

6.  Cement  the  inside  of  the  casing  where  the  cord  patch  is  to  be  placed 
with  three  coats  of  C-25  vulcanizing  cement, 


562 


Automotive  Trade  Training 


Fig.  648.     Showing  tread  laid  back  and  V-shaped  cut  in  tread. 

7.  When  the  cement  is  thoroughly  dry,  remove  the  holland  from  the  gum 
side  of  the  cord  patch  and  insert  the  patch  using  a  paddle,  stitching  down 
carefully  so  that  the  patch  is  not  bridged  and  no  air  is  trapped.  The  oval  in 
the  patch  should  be  directly  over  the  injury  whether  the  injury  is  in  the  center 
of  the  tread  or  not. 

8.  After  the  patch  has  been  stitched  down  into  place,  trim  the  protrud- 
ing edge  or  edges. 

9.  Always  clean  uncured  gum  side  of  the  patch  with  a  cloth  moistened  with 
solvent.  If  any  stock  from  the  holland  sticks  to  the  G-180,  it  can  be  removed 
with  a  rag  moistened  with  water.  It  is  then  thoroughly  cleaned  with  solvent, 
allowed  to  dry  thoroughly  and  applied. 


Fig.  649.     Inside  of  tire,  showing  construction. 


Tire  Care  and  Vulcanizing  553 

10.  After  stitching  the  patch  firmly  into  place,  fill  up  the  injury  on  the 
outside  with  G-170  cushion  gum  up  to  the  top  of  the  breaker  strip. 

11.  The  remaining  part  of  the  injury  should  be  filled  with  G-lOO,  G-105,  or 
G-115  tread  gum. 

12.  Repair   is   ready   for   cure.     See   chart   for   cure   for   regular   sectional 
repairs. 

13.  Cord   separation,   on   the   inside   only,   may   be   taken   care   of  by  the 
Goodyear  Cord  Patch. 

14.  Buff  thoroughly. 

15.  Cement  with   C-25   cement  and  insert  patch   over   weakened  part   of 
carcass. 

16.  Cure  on  inside  vulcanizer. 


Fig.  650.     Inside  section  ready  to  be  built  up. 

JOB  218.     FULL  SECTION  CORD  TIRE. 

For  extremely  large  injuries  it  is  necessary  to  make  a  full  sectional  repair. 
Injuries  that  occur  below  the  tread  line,  if  they  are  too  large  or  in  such  a 
position  that  they  cannot  be  repaired  with  a  cord  patch,  must  also  be  repaired 
with  a  section.  Cut  the  tread  and  breaker  strip  at  point  where  injury  occurs 
and  lay  tread  back  5"  in  both  directions. 

1.  It  is  necessary  to  tear  out  all  of  the  cords  in  the  first  group  on  the 
inside  and  outside. 

2.  These  are  removed  as  follows: 

3.  First  layer  of  cords  allows  a  margin  of  1"  on  either  side  of  the  extreme 
points  of  break  and  from  toe  to  toe  of  bead. 

4.  Second  ply  is  to  be  removed  V2"  inside  of  first  ply. 

5.  Chafing  strips  and  sidewalls  should  be  removed  for  a  distance  of  ^" 
beyond  the  point  where  the  cords  are  removed. 

6.  The  tire  is  then  spread  open  so  as  to  allow  the  removal  of  the  cords  on 
the  inside. 

7.  The  inside  plies  run  opposite  to  the  outside.  These  plies  are  removed 
the  same  as  the  outside.  Chafing  strips  are  laid  back  to  the  toe  of  the  bead 
^"  farther  than  the  widest  ply  taken  out. 

8.  Bufl  the  inside  of  the  casing  far  enough  so  that  a  "cross"  of  cord  fabric 
may  be  inserted  over  the  injury. 

9.  Buff  the  exposed  surface  of  the  tire  thoroughly. 

10.  Cement  both  inside  and  outside  with  three  coats  of  C-15  or  C-16 
vulcanizing  cement. 

11.  Place  cushion  gum  where  the  old  cords  have  been  removed. 


554 


Automotive  Trade  Training 


Fig.  651.     Hole  trimmed  otit  with   sides  tapered. 


12-.     Cushion  gum  should  not  be  stretched  and  should  be  left  full  sfe"  gauge. 

13.  New  plies  of  cords  are  then  inserted  without  lapping. 

14.  The  injury  is  then  filled  from  the  outside  with  G-170  cushion  gum. 

15.  Cushion  gum  is  then  placed  over  the  cemented  tread  surface. 

16.  The  chafing  strip  is  replaced  with  LF-52  fabric. 

17.  Side  wall  rubber  is  replaced  with  G-lOO,  G-105  or  G-115. 

18.  The  tread  is  then  laid  back  and  stitched  down  thoroughly. 

19.  G-170  cushion  gum  is  then  placed  where  the  plies  have  been  torn  out 
on  the  inside. 

20.  The  old  plies  are  replaced  with  new  cord  fabric  in  the  same  manner  as 
the  plies  have  been  replaced  on  the  outside. 

21.  After  the  plies  are  replaced  on  the  inside,  the  same  number  of  plies  of 
fabric  as  have  been  taken  out  on  the  inside  are  inserted,  running  at  right  angles 
to  the  plies  removed  and  from  bead  to  bead  and  forming  a  "cross."  This  over- 
all ply  or  plies  is  2"  wider  than  the  injury  and  applied  skim  coated  side  down. 
The  under  ply  of  the  reinforcement  should  be  made  Yi"  narrower  than  the 
outer  ply  in  order  to  avoid  an  abrupt  change  in  thickness  at  the  edges. 

22.  This  forms  a  reinforcement  over  the  injury. 


Tire  Cake  and  Vulcanizing 


555 


Fig.  652.     Showing  method  of  inserting  cord  patch  inside  of  tire. 

23.  The  section  is  then  cured  in  the  same  manner  as  a  fabric  tire — in  a 
sectional  mold. 

24.  It  may  be  necessary  to  cure  the  section  twice  because  of  its  length. 

25.  However,  effort  should  be  made  to  keep  the  repair  short  enough  so 
that  it  may  be  cured  completely  with  one  cure. 


Fig.  G53.     Outside  of  section  ready  to  be  built  up. 


556  Automotive  Trade  Training 

26.  All  cushion  gum,  G-170,  should  be  used  3*2"  gauge. 

27.  Nominal  size  airbags  are  usually  too  small  in  cross  section  for  use  in 
cord  tires.  Be  careful  in  selecting  your  airbag  for  cord  tire  sectional  work. 
For  example,  a  4^"  sectional  airbag  will  fit  a  4"  cord  tire  better  than  a  4" 
sectional  airbag. 

JOB  219.     CORD  TIRE  FULL  SECTION. 

1.  This  fnethod  is  used  when  the  45°  repair  is  too  long. 

2.  Lay  back  tread  as  described  for  fabric  tire  full  sectional  repair.  The 
length  of  tread  in  inches  to  be  laid  back  will  be  6+  (total  length  of  injury  in 
inches)  +  2  (number  of  plies  removed  from  the  outside  —  1).  The  center  of 
the  section  of  tread  laid  back  should  correspond  to  the  center  of  the  break. 

3.  Remove  the  chafing  strip  and  side  walls. 

4.  The  popular  sizes  of  cord  tires  are  listed  below  with  the  number  of 
plies  in  each  size. 

30x3^^         4  plies  33  x  4^^         6  plies 

32x3%         6  plies  34x4>4         8  plies 

33x4  6  plies  35x5  8  plies 

34x4  6  plies  37x5  8  plies 

32x4^         6  plies 

5.  Repairs  of  this  kind  may  be  divided  in  two  classes:  first  where  the 
break  occurs  between  the  tread  lines  on  the  top  of  the  tire,  second  where  the 
break  occurs  between  the  bead  and  tread  line, 

6.  Repairs  of  the  first  type: 

7.  Remove  one-half  the  total  number  of  plies  from  the  outside  of  the  tire. 
In  eight-ply  tires,  first  ply  should  be  cut  4^"  from  the  extreme  points  of  the 
injury.  For  six-ply  this  distance  will-  be  3%"  and  for  four-ply  2^".  The 
outer  ply  in  all  cases  is  cut  out  around  the  bead  to  the  toe  and  the  ply  beneath 
is  taken  out  to  within  l"  of  the  heel.  When  more  than  two  plies  are  removed 
the  plies  are  stepped  down  l'\  ■ 

8.  Loose  fabric  and  rubber  is  trimmed  out  of  the  break  and  the  repair  is 
then  buffed,  the  inside  of  the  tire  being  buffed  for  a  distance  of  4"  at  each  end 
beyond  the  point  where  the  outer  ply  was  cut. 

9.  Cement  according  to  general  directions  both  inside  and  out. 

10.  Build  up  the  inside  of  the  repair  first  as  follows: 

11.  Stitch  in  a  ply  of  CF-44  skim  coated  side  down  and  cords  running  in 
opposite  direction  to  cords  in  tire.  This  ply  should  extend  %"  on  each  side 
of  the  points  at  which  the  outer  ply  was  cut  and  to  within  V2"  of  the  toe  of  the 
bead.  Over  this  ply  is  placed  another  ply  2"  longer  than  the  first  ply  and 
extending  to  the  toe  of  the  bead. 


Fig.   654,     Inside  of  section   ready   to   be  built   up. 


Tire  Care  and  Vulcanizing 


557 


Fig.  655.     Inside  of  section  built  up  with  crpss. 

12.  This  ply  is  only  stretched  down  to  within  2^/^"  from  the  bead. 

13.  Fill  in  the  hole  through  the  carcass  from  the  outside  with  G-170. 

14.  Build  up  the  outside  by  covering  the  cemented  surface  with  a  ply  of 
G-170  -^i"  gauge.  Replace  the  plies  cut  out  with  CF-44  skim  coated  side  down, 
cords  running  in  same  direction  as  the  original  plies.  New  plies  should  overlap 
^"  and  cords  should  have  the  same  direction  as  those  of  plies  replaced.  The 
last  ply  replaced  should  be  cut  long  enough  to  extend  around  the  bead  on  each 
side  and  1^"  above  the  toe  of  the  bead  on  the  inside  of  the  tire.  After  this  is 
stitched  down,  the  inside  reinforcing  ply  should  be  stitched  over  it. 

15.  Where  the  ply  goes  around  the  bead  it  should  lap  ^"  as  on  the  rest 
of  the  repair. 

16.  Replace  the  side  walls  and  chafing  strips,  lay  back  the  tread  and  fill 
the  hole  with  G-105  tread  stock.  Dust  with  soapstone  and  cure  according  to 
directions  for  full  section  in  sectional  mold. 

17.  Repairs  of  the  second  type: 

18.  In  this  kind  of  repair  where  the  break  occurs  between  the  tread  line 
and  the  bead  it  is  necessary  to  lay  back  the  tread  and  cut  off  the  chafing  strips 
and  side  wall.  Remove  one-fourth  of  the  total  number  of  plies  from  the 
outside  and  one-fourth  from  the  inside.  The  plies  are  taken  out  from  the 
outside  the  same  manner  as  described  for  outside  repair  and  the  plies  on  the 


i''ig.  056.     Section  ready  to  be  built  up. 


558  Automotive  Trade  Training 

inside  are  stepped  out  from  toe  to  toe  and  are  1"  shorter  than  the  largest  ply- 
taken  off  the  outside.     The  remaining  plies  are  stepped  down  l". 

19.  Trim  out  loose  rubber  in  the  break  and  cement. 

20.  Replace  the  plies  in  the  manner  described  for  the  first  type  of  repair, 
placing  a  skim  coat  of  G-170  both  inside  and  out. 

21.  Put    one    reinforcing   ply    on    the    inside    with    cords    running    in    the 
opposite  direction  to  cords  in  last  ply  replaced. 

22.  This  ply  should  be  stitched  down  over  the  last  ply  brought  around  for 
the  outside  of  the  repair. 

■     23.     Cure    the    repair   in    sectional    mold    according    to    directions    for    full 
sectional  cure  as  given  in  thv,  chart. 


Fig.  657.     Section  built  up  before  laying  back  tread. 

JOB  220.  WIDTH  OF  BREAKER. 


Fabric  Tires 

Cord  Tires 

Size  Tire 

Width  of  Breaker 

Size  Tire       Width  of  Breaker 

3" 

3^" 

3^"                         3'' 

3/2" 

2/2" 

4''                             3^" 

4" 

23/4"  • 

4/2"                         4" 

4/2'' 

354" 

5"                                                 ^V2" 

5'' 

4" 

Splices  Yi,"    Splices  not  closer 
than  10" 

JOB  221.  REPAIRING  TREAD  CUTS. 

1.  Tread  cuts  should  be  repaired  at  once  so  that  sand  and  moisture  will 
not  work  into  the  tire  and  cause  separation. 

2.  Bevel  out  injury  down  to  the  carcass  so  that  it  is  free  and  open.  BufT 
thoroughly.  Clean  with  cloth  moistened  with  solvent.  Cement  according  to 
directions. 

3.  When  thoroughly  dry,  fill  injury  with  layers  of  G-lOO,  G-105,  or  G-115, 
depending  upon  the  color  of  the  rubber  in  the  tread  of  the  tire. 

4.  The  injury  is  built  up  higher  than  the  original  tread.  The  original 
tread  pattern  is  then  cut  into  the  raw  stock. 


Tire  Care  and  Vulcanizing  559 

5.  Cure  for  tread  cuts  should  be  taken  from  the  chart. 

6.  In  repairing  the  tread  cut  it  is  essential  that  the  fabric  directly  under 
the  cut  is  free  from  foreign  matter  such  as  dirt  and  moisture. 

7.  If,  on  examination,  it  is  found  that  the  fabric  is  water-soaked  and  full 
of  dirt,  remove  the  first  layer  of  fabric  on  the  outside  in  the  form  of  a  small, 
square  patch. 

8.  In  building  up,  this  should  be  covered  with  G-170  cushion  gum. 

9.  Place  a  piece  of  HF-41,  %"  larger  than  the  piece  taken  out,  in  the  square 
made  above.     Place  G-170  gum  over  the  ply  placed  in  position. 

10.  Then  fill  the  cut  of  the  tread  in  the  same  manner  as  described  above. 

11.  In  case  of  mud  boils  or  sand  blisters,  cut  the  blister  open  and  remove 
all  of  the  loose  rubber  from  the  carcass.     Buff  thoroughly. 

12.  In  case  more  than  one  ply  is  removed,  the  plies  are  stepped  down  l". 

13.  Then  replace  with  HF-41  fabric,  allowing  J/^"  lap  on  the  under  plies 
and  }i"  lap  on  the  last  ply. 

14.  Then  place  an  inside  reliner  extending  from  toe  to  toe  of  the  bead  of 
approximately  l"  more  in  width  than  the  largest  ply  of  new  fabric  replaced  on 
the  outside. 

15.  Fill  in  the  cut  on  the  outside. 

16.  Dust  with  soapstone.     Cure  repair  according  to  chart. 


Fig.  G58.     Filling  in   the   Injury. 

JOB  222.     PRESERVING  THE  TREAD. 

1.  When  vulcanizing  a  section  in  a  non-skid  tire  it  is  not  necessary  to 
disfigure  the  tire  by  a  section  on  which  the  tread  design  is  imperfect,  due  to  the 
old  design  being  flattened  out  in  curing. 

2.  The  design  may  be  preserved  by  the  use  of  a  stiff  paste,  made  of  soap- 
stone  and  water.  When  soapstone  is  used  the  tread  pattern  is  cut  in  the  new 
rubber  before  the  cure. 

3.  Another  method  of  preserving  the  design  is  to  make  up  a  matrix  or 


560 


Automotive  Trade  Training 


negative  pad  from  one  ply  of  LF-52  and  two  plies  of  -h"  gauge  tread  gum. 
The  pad  should  be  wide  enough  to  cover  the  width  of  the  tread  and  long 
enough  to  extend  about  l"  beyond  either  end  of  the  molds  with  which  it  is  to 
be  used. 

4.  Soapstone  the  pad  freely  and  fit  it  over  a  section  of  the  tread  that  is  in 
good  condition.  Insert  a  sectional  air  bag.  Clamp  the  tire  in  the  mold  and 
cure.     (See  table.) 


Fig.  659.     All-Weather   Negative  Pad. 


5.  The  result  will  be  a  perfect  mold  of  the  tread  pattern. 

6.  When  the  repair  is  ready  to  vulcanize  soapstone  the  raw  section  of  the 
tire,  then  take  the  pad  and  apply  C-35  cement  at  the  edges.  Fit  the  pad  over 
the  section;  the  cement  will  hold  it  in  place.     Cure  the  repair  as  recommended. 

JOB  223.     REPAIRING  SCRAPED  SIDE  WALLS. 

1.  Side  wall  repairs  are  of  three  kinds:  (1)  Side  wall  rubber  may  be 
injured  and  no  plies  damaged;  (2)  the  top  ply  may  be  injured  and  plies  cut;  (3) 
the  side  wall  rubber  may  be  chafed  and  several  plies  worn  through  for  the 
entire  circumference  of  the  tire. 

2.  When  the  side  wall  rubber  alone  is  injured,  the  old  rubber  is  trimmed 
away  and  the  exposed  surface  is  buffed  and  cemented.  A  new  side  wall  is 
inserted,  replacing  the  old  rubber, 

3.  When  the  top  ply  has  been  cut  through,  it  is  often  necessary  to  replace 
this  cut  ply  by  a  new  ply  which  is  built  in,  in  a  manner  similar  to  a  quarter 


Tire  Care  and  Vulcanizing 


561 


section.  The  side  wall  and  chafing  strip  are  removed  and  the  ply  is  taken  out 
to  the  tread  line.  The  ply  of  fabric  is  replaced  by  a  new  fabric  extending 
around  the  bead  of  the  tire  to  a  point  half  way  between  the  center  of  the  tread 
and  the  tread  line  on  the  same  side  as  the  chafed  side  of  the  tire. 

4.  When  the  plies  have  been  cut  locally  through  only  a  few  plies  of  fabric, 
it  is  often  more  expedient  to  reinforce  the  inside  of  the  casing  with  a  sectional 
reliner,  trimming  out  the  injury  and  filling  in  with  new  side  wall  rubber.  These 
repairs  may  be  cured  in  either  a  sectional  mold  or  like  a  retread  by  inserting 
the  coil  and  curing  it  in  a  kettle.  Local  repairs  that  have  a  sectional  reliner 
are  cured  according  to  the  chart. 


Fig.  660.     Scraped   side  wall. 

JOB  224.     RETREADING. 

1.  Remove  old  tread  rubber  and  breaker  strip  froni  tread  line,  to  tread 
line. 

2.  Fig.  662  shows  tire  ready  for  retreading. 

3.  Buff  exposed  surface  and  cement  with  three  coats  of  C-15  or  C-16 
vulcanizmg  cement,  accordmg  to  directions. 

4.  Sometimes  when  the  tire  has  been  run  too  long  it  will  be  found  that 
one  or  two  outer  plies  have  been  so  damaged  by  water  and  dirt  working 
through  the  tread  that  they  must  be  removed..  In  this  case  the  injured  ply  or 
plies  should  be  stepped  out  and  replaced  with  new  fabric.  To  do  this  the  plies 
are  stepped. out  on  each  side  of  the  broken  fabric,  keeping  as  close  as  possible 
in  order  to  stay  above  the  flex  points.     Room  should  be  allowed  for  a  ^"  step 


^62 


Automotive  Trade  Training 


Fig.  661.     Scraped  side  wall,   one  or  more  plies  of  fabric  worn  through. 


if  the  under  ply  is  removed.  In  building  up  the  HF-41  is  applied  directly  to 
the  cemented  surface  skim  coated  side  down.  A  Yz"  lap  is  made  on  the  under 
ply  and  a  ^"  lap  on  the  outer  ply. 

5.  G-lOO,  G-105,  G-115  is  used  when  applying  a  plain  laid-up  tread.  The 
gauge  should  be  the  same  as  the  corresponding  camel  back  for  the  same  size 
tire.  (See  chart  for  proper  sizes  and  widths).  When  this  tread  is  laid  up  and 
thoroughly  stitched,  all  air  being  removed,  it  is  placed  on  the  carcass  directly 
over  the  breaker  strip.     It  is  trimmed  at  the  tread  line. 

6.  Camel  back  may  be  used  in  place  of  the  built-up  tread. 

7.  In  some  cases  it  is  necessary  to  put  a  section  in  the  tire  before  it  is 
retreaded.  In  this  case  remove  the  old  tread  rubber,  breaker  and  cushion. 
Trim  out  the  repair  and  rebuild  section  in  the  usual  manner  with  the  exception 
of  applying  the  tread 

8.  This  section  should  be  given  a  semi-cure. 

9.  This  cure  is  sufficient  to  shape  the  beads  and  side  wall  rubber  of  the 
section. 

10.  The  casing  is  then  buffed  and  cemented  and  the  retread  applied  in  the 
usual  manner. 

11.  Goodyear  Camel  Back  is  furnished  to  eliminate  the  plying  up  of 
ordinary  tread  rubber  for  retreading  work. 

12.  Camel  Back  is  applied  in  the  same  manner  as  the  built-up  tread. 


Tire  Care  and  Vulcanizing 


563 


Fig-.  662.    Tire  Buffed  and  ready  for  retreading. 


JOB  225.     BUILDING  UP  THE  RETREAD. 

1.  When  cement  is  thoroughly  dry,  apply  one  ply  of  G-170  cushion  gum 
^^"  gauge.  This  cushion  gum  should  extend  to  within  Vz"  of  the  edges  of  the 
cemented  surface. 

2.  Breakers  should  be  cut  "on  the  straight"  for  fabric  tires  and  on  the 
bias  for  cord  tires. 

3.  Apply  breaker  strip.  (See  chart  for  width  of  breaker  strip  for  various 
sized  tires.) 

4.  In  applying  semi-cured  retread  bands  a  layer  of  ^"  gauge  tread  gum  is 
placed  over  the  breaker  strip  extending  from  tread  line  to  tread  line, 

5.  The  semi-cured  retread  band  is  thoroughly  buffed  and  cemented  with 
three  coats  of  C-15  or  C-16  vulcanizing  cement. 

6.  When  cement  is  thoroughly  dry  the  band  is  placed  on  the  tire. 

7.  A  piece  of  clean  muslin  or  holland  should  be  placed  over  the  cover- 
stock  before  the  band  is  applied.  This  will  eliminate  the  possibility  of  the 
tread  band  sticking  to  the  carcass  before  it  is  centered. 

8.  When  band  is  centered,  remove  the  muslin  or  holland  and  stitch  well, 
stitching  from  the  center  out.    Stitch  between  the  buttoms. 


564  Automotive  Trade  Training 

9.  Be  careful  that  you  have  removed  all  air  blisters  between  the  cover- 
stock  and  the  carcass  proper. 

10.  After  stitching  down  the  band,  the  edges  should  be  trimmed  V^"  above 
the  undercover  line  in  3",  3J/2",  and  4"  tires.  Trim  off  ^"  above  the  under 
tread  line  in  4^"  and  5"  tires. 

11.  Retread  is  ready  for  cure. 


Fig.  663.     Successive  steps  in  building  up   retread,   showing  buffed  surface,  cushion, 
breaker,    under-cover    and    semi-cured    retread    band. 

JOB  226.     CURING  THE  RETREAD. 

Kettle  Cure.-^Insert  steel  coil  of  sufficient  size  to  keef^'^the  toe  of  the  tieads 
1^"  apart. 

1.  Make  a  thick  paste  of  soapstone  and  water  and  fill  the  cavities  in  the 
tread  design  if  semi-cured  band  is  used.  The  paste  keeps  the  tread  design 
from  flattening  out  under  pressure. 

2.  Cover  the  outside  of  the  casing  to  just  below  the  tread  line  with  a  heavy 
jacket  of  cotton  canvas,  or  muslin,  cut  on  the  bias. 

3.  Then  wrap  the  tire  with  cotton  canvas  strips  approximately  2"  in 
width.  This  should  be  wrapped  around  ,  with  a  1"  lap.  Wrap  twice  around, 
reversing  the  direction  the  second  time  around. 

4.  .  Use  extreme  pressure  in  wrapping  the  casing. 

5.  Use  length  and  temperature  of  cure  specified  on  chart. 

6.  When  applying  the  plain  tread,  the  entire  surface  of  the  tread  is  dusted 
with  soapstone,  the  coil  is  inserted,  and  a  heavy  jacket  of  cotton  canyas  or 
muslin,  is  applied,  covering  the  raw  stock.  The  tire  is  then  wrapped  with  strips 
of  cotton  canvas  as  when  retreading  with  a  semi-cured  band.  The  tire  is  now 
ready  for  cure. 

JOB  227.     THIRD  CIRCLE  RETREADING. 

1.  For  one-third  circle  retreaders  camel  back  stock  or  built-up  tread  gum 
is  applied. 

2.  Care  must  be  taken  in  curing  by  one-third  circle  retread  methods  to  get 
•the  best  results  and  minimum  of  defects. 

3.  A  sand  bag  is  used  in  curing  retreads  in  one-third  circle  retreading. 


Tire  Care  and  Vulcanizing 


565 


Fig.   664.     Laying   up   a  tread. 

The  pressure  is  secured  by  means  of  clamps  and  a  pressure  bar.  The  sand  bag 
should  fit  snugly  in  the  casing  and  should  be  just  as  long  as  the  mold.  It 
-should  be  of  sufficient  diameter  to  assure  a  good  pressure  on  the  side  walls. 


Fig.  66&.    Photo  showing  method  of  putting  band  on  tire  with  muslin. 


566 


Automotive  Trade  Training 


Tig.  66C.     Section  of  casing  cut  down  t( 


apstoiu 


iiid    uieth.td   of  wrapping. 


4.  Care  should  be  taken  that  the  pressure  bar  used'on  top  of  the  jand  bag 
is  not  bent  or  out  of  shape.  " 

5.  If  the  pressure  bar  is  out  of  shape,  flat  spots  will  occur  on  the  tread 
surface  between  the  points  directly  under  the  clamps.  The  pressure  bar  shou'd 
not  be  too  large  and  stiff,  otherwise,  the  pressure  will  not  be  distributed  evenly 
and  light  spots  may  result.     The  clamps  should  be  tight?ned  dT.vn  .u^radualiy 


Fig.  6G7.     Third  circle  retreader. 


Tike  Care  and  Vulcan iz inc. 


567 


Rubber  Knife. 


Fig.  668. 


Hard  Casing  Roughing  Brush. 


668  Automotive  Trade  Training 

from  the  center  of  the  mold  out,  so  that  no  air  is  trapped,  which  would  cause 
defects  in  tread.     Tighten  clamps  about  ten  minutes  after  the  cure  is  started. 

6.  The  tire  should  be  kept  in  an  upright  position  so  that  the  tread  design 
or  ribs  are  centered  evenly  around  the  tire. 

7.  The  edges  of  the  tread  gum,  after  it  is  applied  to  the  tire,  should  be 
skived  and  stitched  down  to  a  thin  feather  edge  so  that  a  perfect  union  is 
insured  without  excessive  overflow. 

8.  Be  sure  to  examine  the  casing  during  the  cure  for  air  blisters  at  the 
ends  of  the  section  that  is  being  cured. 

9.  If  these  blisters  appear,  they  should  be  opened  at  once  by  means  of  a 
sharp  awl. 

10.  Sand  used  in  sand  bags  should  be  screened  through  a  20  mesh  sieve. 

11.  It  is  advisable  to  use  a  small  amount  of  fine  flake  graphite  with  the 
sand  to  eliminate  any  bunching  or  caking  and  assist  in  giving  uniform  pressure. 

JOB  228.     RETREADING  CORD  TIRES. 

Retread  the  cord  tire  in  the  same  manner  as  the  fabric  tire. 
After  the  old  tread  is  removed,  inspect  the  tire  carefully.     The  tire  should 
not  be  retreaded  if  it  has  ply  separation. 

The  building  up  and  curing  is  the  same  as  for  fabric  tires. 


CHAPTER  17 

GARAGE  SHOP  REPAIR  METHODS 

JOB  229.     LIFTING  AN  ENGINE  FROM  A  CAR. 

The  use  of  a  crane,  a  heavy  block  and  tackle,  or  chain  block  is  essential  to 
lifting  a  motor  from  a  car.  Various  types  of  cranes  are  in  use.  Where  many 
cars  are  handled  in  a  certain  location  the  traveling  crane,  mounted  overhead 
in  such  manner  that  the  chain  block  may  be  run  to  any  point  over  a  consider- 
able area,  is  best.  The  crane  mounted  on  the  single  track  is  rather  limited  m 
its  service.  The  double  track  overhead  crane  which  permits  of  side  to  side 
motion  as  well  as  movement  along  the  track  is  very  good. 

The  floor  crane  which  is  so  arranged  that  it  may  be  run  under  the  front 
axle  of  the. car  to  lift  out  or  replace  the  motor  is  ideal  for  the  smaller  garages. 
Fig.  669  shows  the  Franklin  crane  of  the  portable  type  being  used  to  replace 


■ 

.^^r- 'v^*"^*"^ 

«^NI' 

«l 

w  ^ 

1  f 

r^'^^^BHB 

^^^H 

^Km/                ,  / 

Infi 

■ 

'/'.-A^^^H 

^^^^E 

yH 

1^^^^^^^ 

IH 

HHm 

Fig.  669.  Lifting  an  Engine  with  a  Portable  Crane, 
the  six-cylinder  engine  in  a  Reo  car  frame.  The  particular  advantage  of  this 
type  of  crane  is  the  ease  with  which  a  heavy  motor  may  be  lifted  out  and  then 
moved  to  any  desired  position.  When  in  use  for  lifting,  the  front  wheels  are 
locked  under  the  frame  to  prevent  the  crane  moving.  Throwing  the  handle 
controlling  these  wheels  forward  releases  the  wheels  and  permits  of  the  crane 
and  load  bemg  moved  about  the  floor. 

The  floor  crane  is  also  used  for  lifting  the  body  or  frame  away  from  the 
rear  axle.  Care  must  be  used  in  makmg  the  hitch  to  prevent  the  top  or  body 
being  injured. 

In  making  a  hitch  on  an  engine  or  other  load  for  lifting  make  very  certain 

569 


570 


Automotive  Trade  Training 


it  is  secure  and  safe.     Ropes  and  wire  are  to  be  avoided  for  this  type  of  work 
Special  clamps  or  a  good  square  link  chain  are  safer  and  better. 

JOB  230.     USING  A  GARAGE  PRESS. 

The  development  of  the  automotive  trades  has  led  to  the  development  of 
special  labor  and  time  saving  equipment.  The  arbor  press  which  is  best  fitted 
for  limited  machine  shop  work  is  not 
always  best  fitted  for  the  wide  range  of 
work  met  with  in  the  garage.  The 
special  garage  presses  such  as  the 
Weaver,  shown  in  Fig.  670,  are  better 
suited. 

In  the  use  of  a  press  of  this  nature 
several  points  must  be  kept  in  mind. 
Owing  to  the  tremenduous  pressure 
the  work  must  be  handled  carefully  to 
avoid  any  damage. 

1.  Adjust  the  table  to  accommo- 
date the  work. 

3.  Make  certain  that  the  work  is 
to  receive  the  pressure  at  the  correct 
point. 

3.  Do  not  attempt  to  press  while 
work  is  resting  on  makeshift  supports. 

4.  Do  not  apply  pressure  with  the 
spindle  or  shaft  being  pressed  setting 
at  an  angle. 

5.  Where  bushings  or  gears  are 
being  pressed  on  make  certain  the 
parts  are  entering  properly. 

6.  It  is  a  good  plan  to  round  the  ends  or  edges  of  the  bushings  jusc  a 
trifle  to  insure  their  pressing  properly  and  not  grabbing  on  the  side  of  ^.the 
retainer. 

7.  Where  work  is  too  long  to  enter  with  the  press  setting  on  the  floor,  it 
may  be  blocked  up  or  even  be  operated  while  laid  on  the  side. 

TAPS  AND  DIES. 

In  order  that  the  student  may  recognize  the  various  sizes  and  kinds  of 
threads  it  io  necessary  for  him  to  spend  some  time  in  studying  them.     While 

there  are  still  a  number  of  spe- 
cial threads  in  use  on  certain 
machines,  standardization  is 
along  the  lines  of  four  only. 

U.  S.  S.— This  is  the  abbre- 
viation for  United  States  Stand- 
ard thread.  This  thread  is  a  V 
thread  with  a  flat  edge,  or  an 
edge  which  just  fails  of  reach- 
ing a  point.  It  is  used  in  all 
manner  of  machinery  and  equip- 
ment. In  automotive  work  it 
is  used  more  for  studs  which 
are  set  in  soft  metal  such  as 
bronze  or  aluminum  or  cast 
iron.  Bolts  with  this  thread 
are    used    for   fastening   on   the 


Fig.  670. 


Using  a  Garage  Press  to  press 
in  ball  cup. 


^HkkkMiH0MMmm 


tut  III 


'ig.    671.     TaptT. 


Plug    an<l    Bottoming    Taps. 


Garage  Shop  Repair  Methods 


571 


body,  bolting  on  fenders,  and  splash  guards,  and  certain  other  types  of  work 
about  a  car. 

S.  A.  E. — This  is  the  abbreviation  for  the  thread  standardized  by  the 
Society  of  Automotive  Engineers  for  use  in  construction  and  assembly  of  most 
parts  about  the  automobile.  The  thread  is  a  V  thread  similar  to  the  U.  S.  S. 
but  will  run  finer  for  the  same  size  of  bolt.  The  student  will  learn  to  recog- 
nize the  difference  between  these  two  threads  very  quickly.  It  is  only  the 
rankest  amateur  who  will  attempt  to  force  an  improper  nut  onto  a  bolt.  This 
thread  was  formerly  known  as  the  A.  L.  A.  M. 

Stove  Bolt  Threads.— This  is  the  third  thread  commonly  found  about  the 


Fig.  672.     Thread  Dies. 

automobile.  Its  use  is  confined  to  rough  work  such  as  bolting  mud  guards 
and  splash  pans  to  the  frame  or  to  each  other.  The  thread  is  still  coarser 
than  the  U.  S.  S. 

Pipe  Threads — This  is  a  thread  used  for  plugs  and  certain  gasoline  and 
water  fittings.  The  Yz"  spark  plug  is  fitted  with  J^"  pipe  threads  which,  being 
on  a  taper  of  Y^'  per  foot,  give  a  wedging  action  as  they  are  screwed  into  the 
cylinder  head.  The  yi"  and  the  ^"  are  favorite  pipe  plugs,  used  for  plugging 
holes  in  housings  provided  for  filling  the  part  with  grease  or  oil.  Pet  cocks 
are  ordinarily  pipe  threads.  The  pipe  thread  is  a  fine  thread  and  may  be 
recognized  by  the  taper.  Since  pipe  is  measured  on  the  inside  the  student 
will  find  a  ^"  pipe  tap  quite  a  bit  larger  than  a  J^"  bolt  tap  and  similarly  with 
other  sizes. 

Depth  of  Thread. — A  full  depth  of  thread  in  a  nut  is  only  five  per  cent 


Tapered 
Fig.  673.     Pipe   Taps. 


Stronger  than  a  75  per  cent  thread.  However  the  work  of  tapping  it  is  three 
times  as  great. 

A  common  nut  drilled  out  so  that  only  a  50  per  cent  thread  is  available 
when  tapped  will  hold  quite  well,  in  fact  it  is  claimed  to  break  the  bolt  in  most 
cases  before  stripping. 

A  75  per  cent  thread  is  much  more  economical  in  tapping  and  yields  a  fine 
margin  of  safety,  this  being  given  as  2  to  1. 


57Z 


Automotive  Trade  Training 


JOB  231.     USING  TAPS. 

Cutting  screw  threads  with  the  hand  taps  is  not  a  difficult  piece  of  work. 
The  beginner  must  learn,  however,  to  recognize  by  the  feel  of  the  strain  on  the 
tap  the  manner  in  which   the  work  is  being  done.     In  the  use  of  small  taps 

TAP  DRILL  SIZES-75%  Depth  Thread 
U.  S.  F.  and  S.  A.  E.  Standard 


gs 

-.T. 

Drill 

?/e 

Hole 

Drill 

J^ 

Thds. 

pcrin 

ss; 

Drill 

•/16 

72 

.049 

3/64 

•/4 

32 

.220 

2 

Vb 

14* 

.805 

'3/6 

t«/.6 

64 

.047 

V64 

'/4 

28* 

.215 

3 

Vs 

12 

.794 

5/64 

'/l6 

60 

.046 

56 

•/4 

27 

.214 

3 

+      7/8 

9 

.767 

<^64 

V64 

72 

.065 

52 

'/4 

24 

.209 

4 

»5/6 

12 

.856 

55/64 

V64 

64 

.063 

'/l6 

+    '/4 

20 

.201 

7 

+     «5/6 

9 

.829 

5^64 

t5/64 

60 

.062 

'/l6 

5/,6 

32 

.282 

^32 

1 

27 

.964 

3'/32 

5/64 

56 

.061 

53 

5/.6 

27 

.276 

J 

1 

14* 

.930 

'5/,6 

3/3? 

60 

.077 

V64 

5/,6 

24* 

.272 

I 

1 

12 

.919 

5^4 

3/32 

56 

.076 

48 

5/6 

20 

.264 

•7/64 

+    1 

8 

.878 

7/8 

+  3/32 

50 

.074 

49 

+  5/6 

18 

.258 

F, 

1'/6 

8 

.941 

'5/6 

3/32 

48 

.073 

49 

3/8 

27 

.339 

R 

1-/8 

12" 

1.044 

13/64 

7/64 

56 

.092 

43 

3/8 

24* 

.334 

Q 

+    1'/fi 

7 

.986 

6H4 

^64 

50 

.090 

43 

3/8 

20 

.326 

2)44 

1^ 

7 

1.048 

13/64 

+  7/64 

48 

.089 

43 

+   3/8 

16 

.314 

5/6 

1/4 

12» 

1.169 

r/64 

•/8 

48 

.105 

37 

7/.6 

27 

.401 

Y 

+    l'/4 

7 

1.111 

17/64 

+   '/8 

40 

.101 

39 

7/6 

24 

.397 

X 

15/6 

7 

1.173 

1'/64 

•/8 

36 

mi 

40 

7/6 

20* 

.389 

W 

13/8 

12- 

1.294 

1>9/64 

'/8 

32 

m 

3/32 

+    7/6 

14 

,368 

U 

+    13/8 

6 

1.213 

17/32 

+  «/i4 

40 

.116 

32 

•/2 

27 

.464 

'5/32 

1'/2 

12* 

1.419 

127/64 

H4 

36 

.114 

33 

•/2 

24 

.460 

29^4 

t    l'/2 

6 

1.338 

1"/32 

^ 

32 

.110 

35 

'/2 

20- 

.451 

29^4 

t    15/8 

5'/2 

1.448 

12^64 

5>62 

40 

.132 

30 

+    V2 

13 

.425 

27/64 

t    13/4 

5 

li55 

19/16 

+  5/32 

36 

.129 

30 

'/2 

12 

.419 

27/64 

t    17/6 

5 

1.680 

1"/.6 

5/32 

32 

.126 

'/8 

Vl6 

27 

.526 

"M 

t    2 

4/2 

1.783 

12^ 

•/64 

36 

.145 

27 

V.6 

M* 

m 

'/2 

t    2'/8 

4'/2 

1.909 

12^ 

+   «yfe4 

32 

.141 

28 

+  Vl6 

12 

.481 

3^ 

t  2 'A 

4/2 

2.034 

2'/3? 

3/6 

36 

.161 

2a 

5/8 

27 

.589 

15% 

t    23/8 

4 

2.131 

2'/8 

3/6 

32 

.157 

22 

5/8 

18' 

.571 

14.5«/» 

t    2'/2 

4 

2.256 

2 'A 

3/6 

30 

.155 

23 

5/8 

12 

.544 

3^64 

t    25/8 

4 

2J81 

23/8 

+    3/6 

24 

.147 

26 

+  5/8 

11 

i36 

17/32 

t    23/4 

4 

2.506 

2 'A 

•3/64 

32 

.173 

17 

•'/.6 

16" 

.627 

5/8 

t  27/e 

3/2 

2.597 

2'9/32 

•3/64 

30 

.171 

'/64 

+  "/6 

11 

.599 

'9/32 

t  3 

3'/2 

2.722 

22^ 

+   13/64 

24 

.163 

20 

3/4 

27 

.714 

2^ 

t    3'/8 

V/2 

2.847 

227/32 

7/32 

32 

.188 

13 

3/4 

16* 

.689 

"/-6 

t     3'/4 

3/2 

2.972 

23/32 

7/32 

28 

.184 

14 

3/4 

12 

.669 

M^ 

t     33/8 

3/4 

3.075 

3'/l6 

+    7/32 

24 

.178 

16 

+   3/4 

10 

.653 

2'/32 

t     3'/2 

3/4 

1200 

33/.^ 

•^ 

32 

J04 

6 

'3/,6 

12 

.731 

^64 

t    35/8 

3/4 

3.325 

3  V.6 

•^4 

28 

.200 

8 

+  '3/l6 

10 

.715 

2^ 

t  33/4 

3 

3.425 

3V<« 

+    'H4 

24 

.194 

10 

7/8 

27 

.839 

27^ 

t  37/8 

3 

3.550 

39/,e 

Ve 

18' 

J21 

5^64    t    4 

3 

3.675 

3«'/.6 

•S.  A.  E.  Standard 


+U,  S,  Standard 


particularly  is  this  true.  A  bit  too  heavy  a  strain  on  the  small  tap  will  cause 
it  to  twist  and  spring;  the  expert  mechanic  will  detect  this  action  immediately 
but  the  apprentice  may  continue  turning  the  tap  holder  and  attempt  to  force 
the  tap  to  turn  with  the  result  that  it  is  broken  off  in  the  nut  or  hole.  The 
correct  procedure  when  the  tap  shows  signs  of  twisting  is  to  carefully  back  it 


Garage  Shop  Repair  Methods  673 

out  and  clear  out  the  cuttings.     The  general  method  of  proceeding  in  the  use 
of  taps  is  as  follows: 

1.  Select  the  tap  needed  for  the  piece  of  work  at  hand. 

2.  Determine  the  size  drill  needed  for  the  blank  hole.  This  may  be 
determined  from  the  table  of  tap  and  drill  sizes,  or  by  measuring  the  diameter 
of  the  bottom  of  the  taper  tap. 

3.  Drill  the  hole  a  bit  deeper  than  the  threads  are  expected  to  go,  if  the 
.work  permits  this. 

4.  Start  the  taper  tap  first  and  run  this  as  far  as  it  will  go  without  striking 
the  bottom  of  the  drill  hole.  Keep  the  tap  working  freely.  Use  oil  for  steel 
or  iron.     Oil  is  not  necessary  on  brass  or  cast  iron. 

5.  Follow  the  taper  tap  with  the  plug  tap. 

6.  Follow  the  plug  tap  with  the  bottoming  tap  if  threads  are  to  be  run  to 
the  bottom  of  the  drilled  hole. 

7.  It  will  be  found  that  the  chips  and  cuttings  must  be  removed  from  the 
hole  as  the  work  progresses. 

JOB  232.     USING  DIES. 

Dies  are  made  either  in  one  piece  or  adjustable.  The  latter  are  the  better 
type  since  the  thread  may  be  made  a  bit  above  or  below  standard  to  fit  special 
cases.  This  feature  allows  of  some  compensation  for  wear  of  the  dies  and 
also  permits  of  their  being  reground.  The  setting  of  the  dies  from  standard 
size  should  not  be  done,  however,  unless  the  reason  is  a  very  good  one  as  it 
is  likely  to  put  unusual  strains  on  the  cutting  edges.  In  using  dies  on  steel 
or  iron  plenty  of  oil  must  be  used.  Lard  oil  is  recommended,  but  failing  this 
use  machine  oil. 

1.  Learn  first  the  exact  die  required  to  cut  the  thread  needed.  Make 
certain  that  the  diameter  of  the  bolt  is  known  and  the  number  of  threads  per 
inch.     Select  the  die  bearing  these  figures  stamped  on  it. 

2.  Start  the  die  on  the  bolt  properlj/;.  Dies  are* made  with  the  first  few 
threads  relieved  to  permit  of  starting  the  work  with  the  least  effort.  This 
provision  also  allowa  .the  work  to  proceed  gradually^,  each  thread  or  tooth 
cutting  a  bit  deeper  thah  th^  one  preceding  it.  Dies  are  also  provided  with 
a  guide  which  is  a  free  fit  dver  the  end  of  the  bolt  or  rod.  This  insures  the 
threads  being  started  and  kept  true. 

3.  Avoid  starting  the  die  with  the  finishing  face  first.  Where  it  is 
necessary  to  cut  threads  veiV  close  to  a  bolt  head  the  die  should  be  started 
correctly  and  run  on  as  far  as  possible,  after  which  it  is  removed  and  the 
finishing  face  started  on  first.  This  arrangement  permits  of  the  die  being 
started  correctly  and  prevents  such  a  great  strain  on  the  finishing  threads  or 
teeth. 

FORGING. 

Practically  all  modern  garages  are  equipped  with  a  forge.  This  is  not  with 
the  idea  of  making  new  parts  but  rather  with  the  idea  of  facilitating  repairs. 
The  automobile  is  constructed  with  many  parts  mOre  or  less  inaccessible. 
Some  special  tool  or  appliance  may  be  needed  in  just  one  instance  "or  to  do  one 
particular  piece  of  work.  While  it  may  take  quite  a  bit  of  work  to  forge  out 
this  special  tool,  it  is  a  saving  of  time  and  expense  in  the  end:  In  other  cases 
a  small  part  may  need  to  be  heated  for  bending,  or  for  straightening.  Certain 
parts  from  wrecked  cars  as  for  instance  front  axles  may  need  to  be  heated  in 
the  forge  to  permit  of  proper  straightening.  The  forge  is  not  used'  a  great 
deal  for  the  welding  about  the  garage.  The  oxygen-acetylene  process  is  far 
better  suited. 

The   student   should   do   enough   forging   that   he   may   feel   confident  to 


574 


Automotive  Trade    j  raining 


proceed   with    the    making   of   punches,    chisels,    and    other    special    tools   and 
appliances. 

Carbon  steels  are  susceptible  to  hardening  and  tempering.  All  tools  and 
certain  parts  of  the  automobile  are  made  from  carbon  steel  or  similar  tool  steel. 
Files  are  a  high  carbon  tool  steel,  and  while  they  may  be  forged  into  a  certain 
shape  for  use  as  tools  for  certain  work  their  carbon  content  is  too  great  for 
work  requiring  much  spring. 

JOB  233.     BUILDING  A  FORGE  FIRE. 

Just  as  in  all  other  classes  of  work,  so  it  is  in  forging.  Certain  funda- 
mental operations  or  processes  are  necessary  to  success.  One  of  the  most 
important  is  ability  to  control  the  fire  properly.    The  following  instruction  will 


Fig.   674.     Forge. 


clear  up  many  points  in  the  mind  of  the  student  as  to  the  proper  method  of 
buildmg  and  maintaining  the  forge  hre.  Hand  forges  are  in  use  more  largely 
than  the  power  blast  for  garage  work 

1.  Owing  to  the  fact  that  a  number  of  men  have  access  to  the  same  forge 
it  is  sometimes  difficult  to  maintain  it  in  good  condition.  The  first  step  on 
attempting  to  start  a  fire  is  to  remove  all  the  coke  left  from  the  previous  fire. 
Coke  is  iron  grey  in  color,  light  in  weight  and  clean  to  handle.  It  is  formed 
by  burning  all  smoke  and  gas  from  green  coal.  Lay  the  coke  to  the  side  or 
place  it  in  a  bucket. 

2.  Level  off  the  cinders  remaining  on  the  hearth.  Clean  any  cinders  away 
from  the  center  of  the  hearth  leavmg  the  center  hollowed  out  down  to  the 
tuyere  iron.  This  hollowed  space  should  be  about  the  size  of  an  ordinary 
wash  basin.  The  tuyere  iron  is  in  the  center  of  the  forge  through  which  the 
air  blast  is  forced  into  the  fire,  and  must  show  at  the  bottom  of  the  hollowed 
space. 


Garage  Shop  Repair  Methods  575 

3.  Make  certain  the  blast  is  working  properly  by  running  the  fan.  It  may 
be  necessary  to  clean  out  the  ash  pit  under  the  tuyere  iron,  for  which  a  trap 
door  is  provided  at  the  bottom  of  the  pit. 

4.  Place  the  kindling  for  the  fire.  This  may  be  paper  and  short  lengths 
of  kindling  wood.     Oil  soaked  rags  are  sometimes  used. 

5.  Light  the  kindling,  and  place  on  enough  blast  to  get  it  blazing  smartly, 

6.  Cover  the  burning  kindling  with  the  coke  which  was  saved  for  this 
purpose.  Keep  the  blast  going  and  in  a  few  minutes  the  coke  will  be  glowing 
white  hot. 

7.  Cover  all  of  the  glowing  coke  which  has  been  heaped  to  a  mound  over 
the  center  of  the  hearth,  excepting  the  very  top  and  center  with  green  coal, 
which  is  a  good  grade  of  smithing  coal  that  has  been  dampened  with  water 
until  it  will  pack.  Leave  the  center  open  to  allow  the  blast  and  smoke  to 
come  out.  Use  the  shovel  to  pack  the  green  coal  tight  around  the  sides  of  the 
mound  of  glowing  coke. 

8.  The  work  may  now  proceed.  The  green  coal  is  gradually  dried  out 
and  coked  up.  By  the  time  the  center  of  the  fire  has  burned  out  the  green  coal, 
with  which  it  was  packed,  will  be  converted  into  coke  to  replenish  the  fire.  At 
this  point  the  smith  pulls  in  the  coke  and  thus  replenishes  the  fire,  which  is 
again  protected  with  a  layer  of  green  coal  packed  all  around  its  base  and  open 
only  on  top. 

9.  When  inserting  the  work  into  the  fire  care  is  used  not  to  destroy  the 
shape  of  the  fire. 

10  It  is  useless  to  attempt  work  until  coke  is  available  for  heating  the 
material.  If  the  coke  is  not  at  hand  in  proper  quantities,  time  will  be  saved  by 
starting  the  fire  and  burning  some  of  the  green  coal  into  coke. 

11  It  IS  useless  to  attempt  work  with  a  fire  which  has  green  coal  in  it,  or 
in  one  which  has  cinders  mixed  with  the  coke. 

12.  Keep  the  hearth  leveled  ofif  and  packed  down  hard  with  cinders.  They 
will  not  burn,  but  serve  as  a  fire  protection  to  the  forge.  They  also  serve  to 
form  the  basin  m  which  the  fire  is  held.  Any  surplus  of  cinders  other  than 
those  needed  for  the  above  purpose  should  be  removed  from  the  hearth.  Do 
not  permit  the  cmder  bed  on  the  hearth  to  be  dug  up  or  become  mixed  with 
green  coal. 

13.  Do  not  use  the  forge  for  a  receptacle  for  tools.  The  hammer  should 
lie  on  the  anvil  when  not  in  use.  The  tongs  should  be  kept  on  a  rack,  and  the 
hardie  by  the  anvil.  The  rake,  poker  and  shovel  may  be  laid  on  the  nicely 
leveled  hearth  provided  the  iorge  is  large  enough,  otherwise  keep  them  on  a 
rack. 

14.  Keep  the  space  about  the  forge  neat  and  clean. 

JOB  234.     FORGING  HAND  TOOLS. 

Cold  chisels,  cape  chisels,  gouges,  punches,  drifts,  cotterkey  extractors,  etc., 
are  hand  tools  readily  forged  by  the  beginner.  After  some  experience,  he  may 
confidently  attempt  the  more  advanced  problems  of  socket  wrenches,  end 
wrenches,  and  ihe  many  problems  of  that  nature.  Bearing  scrapers  are  readily 
forged  either  from  new  tool  steel  or  from  old  files.  Old  files  are  also  adapted 
to  forging  into  punches  and  screwdriver  blades. 

In  attempting  to  forge  out  any  tools  keep  the  following  suggestions  in 
mind: 

1.  Select  stock  suitable  to  the  work.  Cold  rolled  or  mild  steel  cannot  be 
hardened  nor  tempered.     Tool  steel  may  be  secured  from  the  supply  houses. 

2.  With  the  stock  cut  to  the  proper  length,  fit  a  pair  of  tongs  to  the  work, 
A  link  over  the  end  of  the  tong  handles  will  be  of  great  aid  in  holding  the 
work  properly. 


576  AuroMOTivE  Trade  Training 

3.  Heating  tool  steel  is  an  operation  which  requires  care.  The  proper 
forging  heat  is  just  below  the  white  heat  and  while  the  steel  is  in  the  yellow 
heat.  Forging  while  white  hot  will  cause  certain  steels  to  crumble  under  the 
hammer. 

4.  Reheat  the  piece  of  work  before  the  heat  has  dropped  to  a  dull  red. 

5.  When  approaching  the  final  steps  of  the  forging  heat,  care  must  be 
used  not  to  go  above  the  hardening  heat  which  is  a  so-called  cherry  red.  At 
this  heat  the  steel  works  nicely.     Forging  while  red  gives  smooth  surfaces. 

6.  When  drawing  out  any  work,  as  the  work  on  the  punch  would  require, 
do  not  attempt  to  draw  the  work  while  keeping  it  round.  Forge  the  work 
square  and  keep  it  square  until  approximately  the  right  length  has  been  secured. 
The  next  step  is  to  forge  the  punch  to  an  octagonal  shape,  and  the  final  step 
in  the  process  is  to  forge  the  eight  corners  into  sixteen  and  remove  any  trifling 
irregularities.  Attempting  to  draw  out  a  piece  of  steel  or  iron  while  retaining 
the  circular  form  will  result  in  a  split  piece  of  work. 

7.  Move  the  work  under  the  hammer  and  not  the  hammer  over  the  work. 

8.  Skill  comes  with  practice. 

9.  Do  not  attempt  to  har^dle  two  pieces  of  work  at  one  time.  Disaster 
will  follow. 

10.  If  white  starlike  sparks  are  seen  coming  from  the  fire,  steel  or  iron  is 
being  burned.  Just  as  a  piece  of  steel  reaches  the  welding  point  it  gives  off  a 
few  sparks.  Continued  heating  above  that  point  will  result  in  a  badly  burned 
piece  of  work.     Iron  may  be  forged  at  that  temperature,  but  tool  steel  may  not. 

11.  Be  careful  not  to  "miss  the  work,  or  the  hammer  will  rebound  from 
the  anvil  with  great  force.  Standing  well  over  the  anvil  the  hammer  may 
strike  the  workman  in  the  face  doing  serious  injury. 

JOB  235.     HARDENING  AND  TEMPERING. 

After  a  piece  of  tool  steel  has  been  forged  to  the  proper  shape  for  the 
desired  work  or  use,  it  is  essential  that  it  be  hardened  and  tempered  to  with- 
stand the  demands  made  upon  it.  A  cold  chisel  must  have  the  cutting  edge 
hardened  and  tempered.  A  punch  must  have  the  small  end  properly  heat 
treated.  Bearing  scrapers,  screw  drivers  and  wrenches  require  varying  treat- 
ments to  insure  their  proper  standing  up  to  the  work. 

Several  methods  are  in  use  for  hardening  tools  and  likewise  for  drawing  the 
temper.  The  student  will  understand  that  tempering  may  not  be  done  without 
the  hardening  having  first  been  accomplished.  The  two  processes  are  separate 
and  may  not  as  a  rule  be  accomplished  simultaneously.  Where  special  methods 
of  heat  treating  are  in  use  the  single  operation  may  finish  the  work,  but  in  the 
tempering  of  hand  tools  at  tlie  forge  hardening  to  the  full  degree  is  the  first 
step.  This  full  degree  of  hardness  is  then  tempered  to  the  point  necessary  for 
the  use  the  tool,  is  to  be  put  to. 

Hardening. — After  the  tool  has  been  forged  to  the  proper  shape  it  is 
replaced  in  the  fire  and  heated  slowly  to  a  cherry  red.  A  cherry  red  is  about 
1400°  Fahrenheit  and  may  be  recognized  as  a  heat  lying  between  a  red  and 
yellow.  Experience  with  the  steel  at  hand  will  give  the  correct  heat  for 
hardening.  When  the  tool  has  reached  the  proper  temperature  it  is  dipped 
into  cold  water,  as  much  of  the  tool  being  inserted  as  is  to  be  hardened.  In 
the  case  of  a  cold  chisel  or  punch  about  1^"  is  correct.  Allow  this  point  to 
remain  in  the  water  until  cold.  When  removed  from  the  water  the  point  should 
hold  the  water  for  a  short  time  before  it  dries  away. 

The  point  is  now  hardened.  The  heat  remaining  in  the  tool  will  be 
sufficient  to  draw  the  temper.  With  a  piece  of  sandpaper  or  emery  cloth  polish 
the  point  of  the  chisel  or  punch  until  it  shows  bright.     As  the  heat  draws  from 


Garage  Shop  Repair  Methods  577 

the  body  of  the  tool  to  the  point,  colors  will-  appear  on  the  polished  surface  of 
the  tool  which  indicate  with  fair  accuracy  the  degree  of  hardness  remaining, 
or  the  temper  of  the  tool.  When  the  proper  color  appears  plunge  the  entire 
tool  into  the  water.  The  chart  gives  the  colors  and  the  corresponding 
temperature,  and  notes  a  few  tools  with  their  corresponding  colors  and  tempers. 
In  case  the  tool  is  to  receive  the  same  temper  all  over,  it  is  first  heated 
properly  and  thoroughly  hardened,  the  entire  tool  being  cooled  in  the  water 
bath.  To  draw  the  temper  the  outer  surface  of  the  tool  is  first  polished  and  is 
then  heated  gradually  over  a  piece  of  sheet  metal  over  the  forge  fire.  A  gas 
flame  may  be  played  directly  on  the  surface  of  the  tool  to  draw  the  temper. 
The  colors  should  be  watched  carefully  and  when  the  proper  one  is  reached 
the  entire  tool  is  plunged  into  the  water. 

Tempering  Chart. 

Light  straw 430  degrees  ] 

Straw     450  degrees  }■  Lathe  tools. 

Dark  Straw 470  degrees  J 

Light  Brown 490  degrees  (  Milling  cutters,  taps,  dies,  and  reamers. 

Dark  Brown    ....  510  degrees  | 

Light  purple   ....  520  degrees  (  Twist    drills,    flat    drills    and    wood    working 

Dark  purple 530  degrees  )  tools. 

Light  blue   550  degrees  {  Screw  drivers,  punches,  cold  chisels,  etc. 

Blue    560  degrees  j 

Dark  blue 600  degrees 

Black above   650  degrees 

SOLDERING. 

It  is  absolutely  essential  that  the  student  of  automotive  trade  work  acquire 
a  knowledge  of  soldering  and  be  able  to  do  a  neat  piece  of  work.  Soldering 
as  required  about  the  motor  car  is  frequently  difficult  and  tedious.  It  is 
difficult  because  of  the  amount  of  oil,  dirt,  and  grease  which  collects  on  the 
parts  requiring  repairs  of  the  nature  possible  with  soldering.  Gasoline  tubes 
and  tanks,  carburetor  and  vacuum  floats  and  other  parts,  as  well  as  parts  of  the 
electrical  equipment  system  are  those  requiring  a  knowledge  of  soldering  in 
order  to  make  repairs  in  a  workmanlike  manner. 

The  first  essential  in  all  solder  work  is  absolute  cleanliness.  The  second 
is  proper  means  of  heating  the  iron  and  the  third  is  a  good  flux.  Solder  may 
be  purchased  in  the  bar  form  or  in  the  wire  form.  The  last  mentioned  is  most 
suitable  for  the  varied  work  about  the  garage. 

Fluxes. — There  are  a  number  of  fluxes  on  the  market.  If  the  garage  does 
not  do  this  kind  of  work  regularly  the  most  satisfactory  flux  is  what  is  known 
to  the  trade  as  soldering  salts.  This  flux  may  be  purchased  from  the  supply 
houses  in  pound  bottles.  To  use  the  salts  they  are  mixed  with  water.  The 
strength  of  the  solution  may  be  varied  at  will  so  that  a  piece  of  work  requiring 
a  strong  flux  may  be  handled  as  readily  as  a  piece  such  as  tin  which  requires 
only  a  weak  flux. 

Where  a  considerable  bit  of  work  is  done  the  acid  preparation  is  recom- 
mended. To  prepare  this,  secure  muriatic  acid  from  a  wholesale  druggist  or 
the  supply  house.  Place  a  quantity  of  the  acid  in  a  glass  or  earthenware 
vessel.  Add  to  the  acid  as  much  scrap  zinc  as  it  will  eat  away.  This  is  called 
cutting  the  acid. 

For  electrical  work  and  certain  other  work  a  paste  preparation  called 
'"soldering  paste"  is  recommended.  This  may  be  secured  from  supply  houses. 
Powdered  resin  forms  a  splendid  flux  for  electrical  and  similar  work.  Acid 
must  not  be  used  in  certain  places  about  electrical  equipment. 


678  Automotive  Trade  Training 

JOB  236.     TINNING  A  SOLDERING  IRON. 

The  proper  care  of.  the  soldering  iron  is  a  prerequisite  to  good  solder 
work.  The  body  of  the  iron  is  made  of  copper.  This  may  be  filed  or  it  may 
be  drawn  out  on  the  tip  to  the  proper  shape.  In  drawing  out  by  hammering, 
the  copper  is  first  Jieated  to  a  dull  red  and  then  cooled  in  water  thus  annealing 
it.  The  point  as  a  rule  should  be  kept  rather  long.  This  permits  of  doing 
better  work  on  the  small  intricate  parts  needing  repairing,  in  the  average  run 
of  work  in  the  garage. 

1.  With  the  point  of  the  iron  of  the  proper  shape,  it  is  filed  bright  and 
clean. 

2.  Heat  in  the  furnace,  on  the  torch,  or  by  any  other  means.  A  clean 
blue  flame  is  preferred  for  this  work  although  the  iron  may  be  heated  in  the 
coal  fire. 

3.  Remove  the  iron  from  the  fire  and  dip  the  point  into  a  vessel 
containing  a  small  quantity  of  soldering  salts  or  other  flux. 

4.  Work  the  iron  onto  a  piece  of  clean  tin  on  which  a  few  drops  of  solder 
have  been  melted.  Continue  dipping  it  into  the  flux  and  working  on  the  tin 
until  an  even  coat  of  solder  is  provided  well  back  on  the  point  of  the  iron. 

5.  While  working  with  the  iron,  each  time  it  is  withdrawn  from  the  fire, 
it  should  be  dipped  momentarily  into  the  soldering  flux  in  the  vessel  especially 
kept  for  this  purpose.  This  has  the  efifect  of  keeping  the  point  of  the  iron 
permanently  bright.  At  the  end  of  a  day's  work  it  will  be  found  that  a 
surprising  amount  of  dirt,  Cross  or  sediment  has  collected  in  the  bottom  of  this 
vessel. 

6.  Acid  or  other  flux  may  be  used  in  this  process  of  tinning. 

7.  The  usual  method  of  tinning  the  soldering  iron  or  copper  in  the  tin 
shop  is  somewhat  different  from  the  above.  Salamoniac  is  used  to  clean  the 
iron  in  this  case  but  it  is  a  bit  more  difficult  to  manipulate.  Where  it  is  used 
in  a  block  the  solder  is  melted  into  the  hole  caused  by  working  the  iron  in  one 
spot  on  the  surface  of  the  block.  When  used  in  the  powdered  form  the  point 
of  the  iron  is  dipped  into  the  box  containing  the  salamoniac  and  then  the 
operation  carried  out  as  outlined  for  the  flux.  - 

8.  The  coat  of  tin  or  solder  will  be  burned  off  if  the  iron  is  heated  to  too 
great  a  degree.  The  first  sign  of  this  is  a  blue  color  to  the  tin  which  will 
shortly  turn  brown  and  flake  off  if  the  heat  is  continued. 

9.  It  is  useless  to  attempt  even  the  smallest  piece  of  work  without 
properly  tinning  the  iron. 

JOB  237.  SOLDERING  A  LEAKY  CARBURETOR  FLOAT. 

In  many  cases  the  hollow  metallic  float  is  in  use  in  carburetors.  In  the 
course  of  months  of  service  the  gasoline  will  in  some  cases  find  its  way  into 
the  inside  of  the  float.     To  correct  this  trouble  proceed  as  follows. 

1.  The  presence  of  gasoline  is  detected  by  failure  of  the  float  to  operate 
properly.  Remove  the  float.  Shaking  it  past  the  ear  of  the  workman  will 
give  forth  the  sound  indicating  a  confined  liquid. 

2.  If  not  certain  where  the  gasoline  entered  the  float  place  a  pan  of  water 
on  the  stove  and  bring  it  to  the  boiling  point.  Place  the  float  in  this  pan.  The 
gasoline  vaporizing  at  a  point  lower  than  that  of  the  boiling  point  of  the  water 
will  be  driven  off  from  the  float  in  the  form  of  bubbles.  The  points  at  which 
the  bubbles  appear  indicate  the  points  at  which  the  gasoline  entered. 

3.  Punch  two  small  holes  in  the  float  on  the  opposite  sides. 

4.  Blow  into  one  of  these  and  all  of  the  gasoline  will  be  forced  out  of  the 
lov/er  one. 


Garage  Shop  Repair  Methods 


579 


5.  After  all  the  gasoline  is  out,  the  float  may  be  repaired  by  soldering  the 
two  holes  punched  in  the  float  and  those  located  by  the  above  method. 

6.  Too  much  solder  piled  on  the  float  will  take  away  its  buoyancy.  A 
very  thin  coat  is  sufficient  to  hold. 

JOB  238.     REMOVE  CARBON  BY  BURNING. 

In  certain  types  of  engines  which  are  not  fitted  with  removable  heads,  the 
job  of  removing  carbon  is  rather  difficult.  Scrapers  may  be  used  but  this  is  a 
tiresome  tedious  task.     Since  carbon  and  oxyf^en  have  a  great  affinity  for  each 

Decarbonizer  Regulator. 


Oxygen  Tank  Valve. 


Oxweld  Carbon 

Removing  Blowpipe 


Flexible  Brass  Tip 


Fig.   673.     Oxweld   Carbon    Removing   Outfit. 


580 


Automotive  Trade  Training 


Fig.  676.     Oxygen  and  Natural  Gas  Lead  Burning  Equipment   (Oxweld). 

other,  this  fact  is  taken  advantage  of  and  oxygen  from  the  welding  tank  is 
used  to  complete  combustion  and  burn  out  the  carbon  from  the  inside  of  the 
cylinder  walls.     Fig.  675  shows  the  type  of  blowpipe  used  for  this  work. 

1,  Remove  a  spark  plug  or  a  port  plug  from  the  engine  cylinder. 

2.  Put  the  piston  in  the  cylinder  being  worked  on,  on  T.  D.  C.  compres- 
sion stroke. 


Fig.  077.     Oxygen  and  Acetylene  Lead  Burnin-  Enuipment   (Oxweld). 


Garage  Shop  Repair  Methods 


581 


3.  Light  a  match  and  permit  it  to  burn  until  the  match  stick  is  well  afire. 

4.  Having    the    oxygen    regulator    valve    and    blowpipe    set    for    a    light 
pressure  and  ready  to  operate,  the  lighted  match  is  dropped  into  the  cylinder. 

5.  Immediately  the  long  flexible  tube  of  the  blowpipe  is  inserted  and  the 
combustion  of  the  oxygen  takes  place.     This  is  evidenced  by  brilliant  white 


Oxweld   Lead   Burning   Torch. 


Sparks  coming  from  the  cylinder  and  a  roaring  sound.  Sometimes  in  cases  of 
cylinders  very  badly  carbonized  the  combustion  is  accompanied  with  loud 
explosion-like  reports.  Keep  the  tip  of  the  blowpipe  moving  about  in  the 
cylinder  until  all  recesses  have  been  reached.  When  no  more  carbon  is  present 
the  combustion  can  no  longer  be  maintained.  Test  the  cylinder  after  the  flame 
goes  out  by  dropping  in  another  burning  match  and  attempting  to  start 
combustion. 

6.     Treat  each  cylinder  in  turn. 

LEAD  BURNING. 

Storage  battery  work  requires  a  knowledge  of  lead  burning  or  lead  welding. 
Whenever  two  pieces  of  the  same  metal  are  joined  together  by  fusion  they 
are  said  to  be  welded  together.     Fusion  means  that  they  are  heated  to  such  a 


Fig. 


679.     Oxweld  lead-burning   equipment   using  oxygen   and   city   gas- 
battery   terminal  straps. 


-welding 


582 


Automotive  Trade  Training 


point  that  they  melt  and  are  thus  joined  in  one  piece.  In  welding  lead  the  filler 
rod  used  is  lead.  The  groups  of  plates  are  burned  together.  This  work  is 
done  in  the  factory.  Where  a  single  plate  is  joined  to  an  old  group  it  must  be 
burned  in,  as  lead  welding  is  called  in  the  repair  shop.  The  lead  connector 
straps  are  burned  to  the  group  posts.  Lead  burning,  has  been  found  to  be  the 
most  satisfactory  means  of  joining  the  battery  parts  together.  Any  other 
method  is  very  likely  to  cause  trouble  due  to  the  corrosive  effects  of  acid. 

Figs.  676  to  678  show  lead  burning  equipment.  Fig.  677  shows  the  oxygen- 
acetylene  outfit  as  made  by  the  Oxweld  Acetylene  Co.  In  this  instance  an 
acetylene  gas  tank  similar  to  that  used  for  automobile  lighting  is  used  to  supply 
the  acetylene  gas.  The  oxygen  is  supplied  from  the  taller  of  the  two  tanks. 
Oxygen  is  a  commercial  product  and  may  be  secured  in  any  of  the  larger  cities. 
The  same  blowpipe  shown  in  Fig.  676  may  be  used  with  oxygen  and  natural  or 
artificial  gas.  Certain  companies  make  torches  suitable  for  oxygen  and 
hydrogen. 

In  actual  lead  burning  the  greatest  difBculty  is  to  bring  the  parts  to  the 
fusing  point  without  having  the  walls  break  down  and  run  away.  Lead  will 
retain  its  shape  until  the  melting  point  is  reached  over  a  considerable  area. 
When  it  starts  to  collapse  the  action  is  very  sudden.  In  burning  lead  straps 
onto  the  storage  battery  care  must  be  used  to  prevent  the  entire  end  of  the 
strap  reaching  the  melting  point.     Too  large  a  flame  will  result  in  this  trouble. 

The  lead  burning  operation  may  also  be  used  about  the  battery  shop  to 
burn  leaden  vessels  together.     These  vessels  are  used  as  acid  containers. 

The  small  flame  of  the  lead  burning  outfit  is  of  service  in  welding  thin 
sheet  metal,  or  in  brazing  small  parts. 


Fig.   680.     Oxweld    burning   on    battery    connecting    straps. 


Garage  Shop  Repair  Methods  583 

JOB  239.     BURNING  CONNECTOR  STRAPS  ON  BATTERIES. 

In  dismantling  a  battery  the  lead  connector  straps  are  removed  by  drilling. 
Assemble  these  in  place  and  proceed  to  burn  them  onto  the  posts  as  indicated 
in  Fig.  680  and  the  steps  outlined  below. 

1.  Have  the  terminal  post  extending  into  the  strap  end  about  one-third  of 
the  way. 

2.  Place  the  flame  into  the  hole  until  it  is  almost  against  the  top  of  the 
post. 

3.  The  top  of  the  post  and  the  bottom  of  the  link  or  strap  should  be 
melted  together  as  rapidly  as  possible. 

4.  Fill  the  hole  with  the  welding  rod  seeing  that  the  portions  filled  in 
actually  fuse  with  the  walls  of  the  hole. 

5.  It  is  sometimes  advisable  to  only  partially  burn  in  the  one  end  before 
giving  it  a  chance  to  cool,  thus  preventing  it  breaking  down. 

6.  After  the  link  is  welded,  the  top  is  leveled  ofif  with  the  blowpipe.  Use 
a  wire  brush  to  remove  any  oxide  or  scum  tending  to  collect  on  the  top  of  the 
finished  weld. 

OXY-ACETYLENE  WELDING. 

Oxy-acetylene  welding  consists  of  melting  the  edges  of  two  pieces  of  metal 
so  that  they  run  together  and  become  solid  when  cold.  In  order  to  do  this  a 
very  hot  flame  is  used.  This  flame  is  produced  by  burning  together  two  gases, 
acetylene  and  oxygen.  The  equipment  required  consists  of  a  cylinder  or  tank 
of  oxygen,  a  tank  of  acetylene,  two  regulators  or  reducing  valves — one  for  the 
acetylene  tank  and  the  other  for  the  oxygen  tank — a  welding  blowpipe,  and  two 
pieces  of  hose  to  connect  the  welding  blowpipe  to  the  regulators. 

Oxygen. — Oxygen  is  a  gas  that  is  used  to  help  burn  the  acetylene.  If  it 
were  not  for  this  gas,  the  high  temperature  of  the  flame  could  not  be  secured. 
Oxygen  does  not  burn  itself.  It  merely  helps  the  other  gas  to  burn.  It  has 
no  odor  and  is  invisible.  It  is  usually  supplied  in  steel  cylinders  or  tanks.  The 
standard  cylinders  hold  200  cubic  feet  of  oxygen.  The  oxygen  is  pumped  into 
these  cylinders  at  1800  lbs.  pressure.  The  amount  of  oxygen  in  a  cylinder  can 
be  determined  by  looking  at  the  high  pressure  gauge  of  the  regulator.  We 
know  that  when  the  cylinder  is  filled — when  the  high  pressure  gauge  shows 
1800  lbs. — there  are  200  cubic  feet  of  oxygen  in  the.cylinder.  If  the  pressure  is 
900  lbs.,  which  is  one-half  of  the  pressure  when  filled,  there  will  be  just  half  as 
much  oxygen  in  the  cylinder,  or  100  cubic  feet.  Likewise,  if  pressure  on  the 
big  gauge  should  show  450  lbs.  in  the  cylinder,  there  would  be  one-quarter  as 
much,  or  50  cubic  feet.  In  general,  for  every  9  lbs.  pressure  below  the  filling 
pressure  of  1800  lbs.,  there  will  be  1  cu.  ft.  less  of  oxygen  in  the  cylinder.  A 
mixture  of  oxygen  and  gas,  being  explosive,  should  be  avoided  in  the  presence 
of  a  flame.  Oxygen  also  will  combine  with  grease,  oil,  or  other  inflammable 
materials  with  explosive  violence.  The  oxygen  regulator  and  the  valve  of 
the  oxygen  cylinder  should  therefore  not  be  greased  or  oiled  at  any  time.  Care 
must  be  taken  that  the  gauges  on  the  regulator  have  no  oil  or  grease  on  them. 
An  oxygen  cylinder,  when  filled,  should  be  handled  carefully,  because  there  is 
such  a  high  pressure  within  it.  Do  not  knock  it  over  or  drop  it.  When  the 
cylinder  is  not  in  service,  the  valve  should  be  protected  by  means  of  a  cap, 
which  comes  with  it.  Before  attaching  a  regulator  to  the  cylinder  valve, 
always  first  'crack"  the  valve  (open  the  valve  slightly)  both  to  clean  out  the 
valve  and  to  see  that  it  is  operating  properly. 

Acetylene. — Acetylene  is  the  gas  that  burns  in  the  oxy-acetylene  flame. 
When  it  is  burned  alone,  without  any  previous  mixture  of  oxygen,  it  produces 
a  yellowish,  smoky  flame.  When  mixed  with  oxygen,  it  produces  a  bluish 
white  flame.    It  is  an  invisible  gas,  but  has  a  distinct  odor. 


584 


Automotive  Trade  Training 


Acetylene  is  made  by  dropping  a  grayish,  stone-like  substance,  called 
calcium  carbide,  into  water.  The  acetylene  bubbles  up  through  the  water, 
leaving  a  white  sludge  at  the  bottom  of  the  vessel.     This  sludge  is  slaked  lime. 

The  machine  in  which  acetylene  is  made  is  called  an  acetylene  generator. 


Oxweld  Welding  Unit 

Fig.  681. 

Acetylene  Tanks. — It  is  not  possible  to  compress  acetylene  at  a  high 
pressure  into  an  empty  tank,  as  is  done  with  oxygen.  This  is  because  acetylene 
at  a  high  pressure  will  explode.  For  this  reason  a  dififerent  style  of  tank  is 
used.  Inside  the  tank  is  placed  a  material  that  is  porous.  This  material  is 
soaked  in  a  liquid  called  acetone.  Acetylene  will  be  dissolved  in  this  liquid 
just  like  sugar  is  dissolved  in  water.  When  acetylene  is  pumped  into  a  tank  of 
this  kind,  it  is  safe.  It  is  never  pumped  up  to  a  pressure  above  250  lbs.  The 
usual  tank  of  acetylene  contains  300  cubic  feet  of  gas. 

No  blowpipe  that  will  empty  it  in  less  than  seven  hours  should  be  used  on 


Garage  Shop  Repair  Methods 


585 


any  acetylene  tank.  If  the  tank  is  emptied  in  a  shorter  time  than  this,  the 
liquid  will  be  drawn  out  of  the  tank.  Do  not  drop  or  jar  an  acetylene  cylinder. 
Handle  it  carefully.  Always  keep  an  acetylene  cylinder  in  as  cool  a  place  as 
possible.  Do  not  stand  it  near  a  fire.  If  possible,  it  should  be  kept  out  of  the 
hot  sun. 

Before  connecting  an  acetylene  regulator  to  a  tank,  be  sure  that  the 
cylinder  valve  is  operating  properly  and  that  there  is  no  leakage  around  the 
nut  of  the  stem.     Because  acetylene  is  inflammable,  all  leaks  in  the  cylinder 


MGM  PRBSSURt  CALVE 


DfAPHRAGM 


HANDLE 


COflNECTtNC  NUT 


DOST  PLUG 
y/ALVE 

NOZZLE 
OUTLET  CONJ^ECTION 


Fig.  682.     Regulator. 

valve,  hose,  and  connections  should  be  avoided.  If  there  is  a  cap  supplied  for 
the  tank  valve,  always  see  that  this  is  in  place  before  moving  the  cylinder.  Do 
not  transfer  actylene  from  the  cylinder  to  an  empty  tank.  Avoid  large  volumes 
ol  acetylene  under  pressure.  Acetylene  will  act  on  pure  copper  so  that  it  will 
produce  an  explosive  compound.  Because  of  this,  never  use  copper  in  acetylene 
equipment.  Brass  or  bronze,  however,  can  be  safely  used.  Never  use 
acetylene  at  any  time  at  a  pressure  above  15  lbs.  Beyond  this  it  is  dangerous. 
Do  not  attempt  to  locate  a  leak  in  the  acetylene  connections  with  an  open 
flame.  To  locate  a  leak  use  soap  and  water  with  a  brush.  When  the  leak  is 
located,  bubbles  will  appear. 

Because  acetylene  is  not  compressed  in  an  empty  tank  like  oxygen,  but  is 
dissolved  m  a  liquid,  it  is  not  possible  to  determine  the  amount  of  acetylene 
being  used  by   the   gauge   readings.     This   may  be   determined,   however,   by 


Om^N  VALVE, 


CXYCEN  C/^AMBFR  _ 


/NJECTOR 


Fig.  683.    Blowpipe. 


586 


Automotive  Trade  Training 


weighing  the  tank  before  and  after  the  job.  There  are  14J/^  cu.  ft.  of  acetylene 
to  a  pound. 

Regulator  or  Reducing  Valve. — A  regulator  or  reducing  valve  is  used  in  an 
oxy-acetylene  unit  to  reduce  the  pressure  of  the  gas  and  to  keep  this  pressure 
constant  or  even.  Fig.  682  shows  a  section  of  one  type  of  regulator.  The 
regulator  is  a  delicate  device,  very  sensitive,  and  must  be  handled  very  carefully. 
Never  drop  or  jar  it.  Do  not  use  oil,  grease,  or  such  material  for  lubrication 
in  connection  with  the  oxygen  regulator.  Keep  as  much  dust  and  dirt  out  of 
it  as  possible,  by  inserting  the  dust  plug  when  the  regulator  is  not  in  service. 
Do  not  change  the  regulator  from  one  cylinder  to  another  without  taking  the 
pressure  off  the  diaphragm,  which  can  be  done  by  turnmg  the  handle  to  the  left. 
A  regulator  should  not  be  repaired  by  any  but  skilled  workmen.  Do  not 
replace  diaphragms,  valve  seats,  springs,  or  other  wearing  parts,  except  with 
those  actually  manufactured  for  the  regulator. 

Welding  Blowpipe. — Fig.  683  represents  a  welding  blowpipe.  The  blow- 
pipe is  the  instrument  which  is  used  for  welding  It  is  designed  to  be  easy  of 
control  and  manipulation.  It  consists  of  a  tubular  handle,  in  one  end  of  which 
is  a  valve  body  carrying  both  the  oxygen  and  acetylene  valves.  On  the  other 
end  is  a  head  into  which  are  inserted  welding  heads  or  tips  of  different  sizes. 
The  mixture  of  gases  occurs  in  these  tips.  If  the  blowpipe  is  handled  properly, 
it  should  not  require  a  great  amount  of  attention.  It  should  only  be  necessary 
to    clean    the    removable    and    working   parts    and    occasionally    the    tips    and 

WELDING  TABLE 


Size 

Per  Hour 

Per  Linear  Foot 

Thickness 

of 

Metal 

of 

Welding 

Head 

Oxygen 
Pressure 

Speed 

Gas  Consumption 

Gas  Consumption 

Iron 

or 

Best 

Shop 

Filling 

Tip 

Lb.  Per 

Condition 

Practice 

uxygen 

Acetylene 

Oxygen 

Acetylene 

Wire 

In. 

Sq.  In. 

Lm.  Ft. 

Lin.  Ft 

Cu   Ft 

Cu.  Ft. 

Cu.  Ft 

Cu.  Ft 

Lb. 

W-3    W-1 

W-3    W-] 

A=No.  28 

1 

4 

30 

26 

3.5 

3.S 

0.14 

0.13 

A=No.  22 

1        2 

6       9 

26 

22 

4.5 

4.2 

0.20 

0.19 

0.005 

A=No.  18 

2 

8 

23 

19 

5.5 

5.2 

0  29 

0.27 

0.007 

,^=No.  16 

3       3 

10       10 

21 

17 

6.6 

6.2 

0.39 

0.37 

0.01 

A=No.  13 

4       4 

11       11 

17 

14 

8.7 

8.3 

0.62 

0.59 

0.02 

K=No.  11 

5       5 

12       12 

14 

ny2 

10.8 

10.2 

0.94 

0.89 

0.04 

6 

14 

11 

9 

15.0 

14.2 

1.67 

1   58 

0.08 

7 

16 

9 

7 

19.2 

18.3 

2.74 

2.62 

0.15 

U 

8 

19 

6M 

4K 

27.6 

26.3 

6.13 

5.85 

0.3 

10 

21 

43/2 

3 

36.0 

34.3 

12.0 

11.4 

0.6 

M 

12 

25 

2H 

I'A 

52.8 

50.4 

35.2 

33.6 

1.4 

1  and  Over 

15 

30 

2 

1 

69   7 

66.3 

69.7 

66.3 

2  4 

Fi£    eS4,    Blowpipe. 


Garage  Shop  Repair  Methods 


687 


passages  of  the  welding  heads.  The  tips  should  never  be  cleaned  out  with 
anything  but  a  soft  copper  or  brass  wire.  If  something  harder  is  used,  the 
hole  will  become  larger  and  the  head  will  not  work  so  well.  Occasionally  dirt 
can  be  blown  out  of  the  head  by  means  of  high  oxygen  pressure.  If  the  flame 
is  not  properly  adjusted,  or  the  tip  becomes  clogged,  the  blowpipe  may 
backfire.  When  this  occurs,  close  the  acetylene  valve  for  a  few  seconds.  Then 
open  this  valve  fully  and  re-light  the  blowpipe.  If  the  backfire  continues, 
close  both  the  acetylene  and  oxygen  valves,  then  relight  the  blowpipe.  If  the 
blowpipe  becomes  heated,  it  may  be  cooled  by  plunging  it  into  a  bucket  of 
water.  When  this  is  done,  be  sure  that  the  acetylene  has  been  shut  off  and  a 
small  quantity  of  oxygen  is  passing  through  the  blowpipe. 

The  blowpipe  may  be  cleaned  by  removing  both  the  acetylene  and  the 
oxygen  hose  and  then  connecting  the  tip  of  the  head  to  the  oxygen  hose.  Then 
turn  on  about  30  lbs.  oxygen  pressure.     The  acetylene  valve  must  be  opened 


Fig.  685.    Oxweld  welding  heads. 


and  the  oxygen  valve  closed.  This  will  drive  any  dirt  or  carbon  through  the 
larger  acetylene  passages.  After  this  is  done,  the  acetylene  valve  should  be 
closed  and  the  oxygen  valve  opened.     This  will  clean  out  the  oxygen  passages. 

Hose. — Two  colors  of  hose  are  used,  black  tor  acetylene  and  red  for 
oxygen.  This  is  to  prevent  interchanging  when  connecting  the  apparatus. 
All  hose  connections  must  be  tight.  A  good  hose  clamp  should  be  used.  Both 
acetylene  and  oxygen  hose  should  be  blown  out  occasionally  so  that  dirt  and 
dust  will  not  be  carried  into  the  blowpipe. 

Welding  Heads. — There  are  ten  sizes  of  welding  heads  supplied  with  a 
blowpipe.  Each  of  these  heads  gives  a  certain  size  flame.  Each  of  these 
flames  is  to  be  used  on  different  thicknesses  of  metal,  as  is  shown  by  the  table 
on  page  586.  The  acetylene  pressure  tor  all  the  heads  is  the  same — namely, 
1  lb.  The  oxygen  pressure  varies,  ranging  trom  9  to  30  lbs.,  according  to  the 
size  of  the  head. 

Oxy-Acetylene  Flame. — When  the  oxy-acetylene  flame  has  just  the  right 
proportion  of  each  gas,  it  is  called  neutral.  This  is  shown  by  a  clearly  defined 
central  cone,  bright  bluish  green  in  color,  surrounded  by  a  bushy,  weak  flame, 


588  Automotive   irade  Training 

purplish  yellow  in  color.  When  too  much  oxygen  is  used,  this  central  cone  or 
jet  becomes  bluer  in  color,  and  loses  the  greenish  tinge;  it  is  not  so  clearly 
defined.  When  too  much  acetylene  is  used,  the  jet  becomes  bluish  white  and 
is  streaky.  The  neutral  flame  should  always  be  used.  The  student  should  test 
his  flame  from  time  to  time  as  he  is  welding.  This  is  done  by  turning  on  a 
slight  excess  of  acetylene,  by  means  of  the  acetylene  valve,  and  then  trimming 
it  down  so  that  a  neutral  flame  is  produced. 

CONNECTING  AND  STARTING  THE  WELDING  UNIT. 

Attaching  Regulator  That  Controls  Flow  of  Oxygen. — The  oxygen  tank  is 
the  taller,  with  the  flat  bottom  and  the  bullet  shaped  head,  covered  with  a 
metal  cap.  This  cap  must  be  unscrewed.  Under  the  cap  is  a  valve.  Slightly 
open  this  valve  to  allow  the  oxygen  to  escape  in  order  to  remove  the  particles 
of  dust  or  dirt  which  may  have  collected.  The  tank  is  usually  painted  gray 
and  green,  red,  yellow,  or  dark  green.  With  each  outfit  is  furnished  a  two- 
gauge  regulator  painted  red.  Remove  the  dust  plug  from  the  regulator  union 
nut.  Attach  this  regulator  to  the  oxygen  cylinder  valve  by  means  of  the  union 
nut  in  the  back  of  the  regulator.  Be  sure  that  this  nut  is  pulled  up  tight  so 
that  no  oxygen  will  leak.  With  each  regulator  is  furnished  a  piece  of  red 
hose.  This  hose  must  be  connected  with  the  outlet  connection  of  the  regulator. 
Be  sure  that  this  connection  is  tight. 

Attaching  Regulator  That  Controls  Flow  of  Acetylene. — The  acetylene 
tank  is  the  shorter  and  stouter  of  the  two  tanks,  and  has  a  depression  at  both 
ends.  In  one  of  these  depressions  is  fixed  a  valve  of  the  same  type  as  the' 
valve  in  the  oxygen  tank.  These  tanks  are  always  painted  black  and  have  a 
name  plate  on  them  giving  the  quantity  of  gas  that  the  tank  contains. 

Open  the  valve  very  slightly  to  blow  out  any  dirt  that  may  have  accu- 
mulated. With  each  outfit  is  furnished  an  adapter,  which  is  a  small  curved 
brass  connection  that  connects  the  tank  and  regulator.  This  adapter  must  be 
fitted  to  the  valve.  Most  acetylene  cylinder  valves  have  left-handed  threads, 
and  for  this  reason  the  adapter  is- left-handed.  When  the  adapter  hks  heen 
attached  to  the  cylinder  by  means  of  the  male  connecting  nut  and  stud,  the 
regulator  is  fastened  to  the  other  end  of  the  adapter  by  means  of  a  connecting 
nut  similar  to  the  nut  of  the  oxygen  regulator,  but  threaded  left-handed.  The 
acetylene  regulator  is  usually  the  same  in  design  as  the  oxygen  regulator, 
except  that  it  is  painted  black  and  the  gauges  on  it  are  for  low  pressure.  When 
the  acetylene  regulator  is  tightly  connected,  the  acetylene  hose  is  attached  to 
the  outlet  of  the  regulator.     This  hose  is  usually  black  in  color. 

Blowing  Out  Hose  to  Clean. — Before  going  any  farther,  it  is  necessary 
that  we  blow  the  hose  out  to  remove  dirt  and  dust.     This  is  done  as  follows: 

Slowly  turn  on  the  oxygen  valve.  This  valve  should  be  turned  to  the  left 
by  means  of  the  hand  wheel  on  it  until  the  valve  is  open  as  far  as  it  will  go. 
The  pressure  of  the  oxygen  in  the  cylinder  will  show  on  the  big  gauge.  If  the 
cylinder  is  full  this  big  gauge  will  read  100  per  cent  at  1800  lbs.  Then  turn  the 
handscrew  of  the  regulator  to  the  right  until  oxygen  passes  through  the  hose. 
Keep  turning  the  handle  until  a  pressure  of  about  5  lbs.  shows  on  the  small  or 
low  pressure  gauge.  Let  the  oxygen  pass  through  this  hose  for  a  few  seconds, 
and  then  turn  the  handle  of  the  regulator  to  the  left  until  the  flow  of  oxygen 
stops. 

Now  slowly  open  the  valve  on  the  head  of  the  acetylene  tank  by  means  of 
the  wrench  supplied.  This  valve  should  never  be  opened  more  than  two  full 
turns.  The  pressure  in  the  acetylene  tank  will  then  be  shown  on  the  big  gauge. 
This  pressure  will  be  about  250  lbs.  when  the  tank  is  full.  The  handscrew  of 
the  regulator  should  then  be  turned  to  the  right  until  a  small  amount  of 
acetylene  passes  through  the  hose.    Care  must  be  taken  that  no  fires  or  flames 


Garage  Shop  Repair  Methods 


589 


are  near  at  the  time,  otherwise  the  acetylene  will  become  lighted.  The  gas  is 
allowed  to  flow  through  the  hose  until  all  dirt  is  removed.  This  should  not 
take  more  than  five  seconds.  When  the  hose  is  clean,  the  handle  of  the 
regulator  should  be  turned  to  the  left  until  the  flow  of  gas  is  stopped. 

Connecting  Blowpipe. — We  are  now  ready  to  connect  the  blowpipe  to 
the  hose.  First,  connect  the  oxygen  hose  from  the  oxygen  regulator  to  the 
hose  connection  on  the  blowpipe  marked  oxygen.  Likewise  connect  the 
acetylene  hose  to  the  blowpipe  valve  marked  acetylene.  Then  select  the 
proper  welding  head  or  tip  that  is  to  be  used  according  to  the  chart  or  table 
furnished  you,  and  screw  it  carefully  into  the  blowpipe.  Turn  on  the  oxygen 
by  means  of  the  handscrew  of  the  oxygen  regulator  until  the  pressure  on  the 
small  gauge  is  as  given  on  the  chart.  Be  sure  that  when  this  is  done  the 
oxygen  valve  on  the  blowpipe  is  open.  Then  close  this  valve,  and  open  the 
acetylene  valve  on  the  blowpipe.  Now  turn  the  handscrew  on  the  acetylene 
regulator  to  the  right  until  acetylene  is  passing  through  the  blowpipe,  and 
close  the  acetylene  valve  on  the  blowpipe. 

OXYGEN 
REGULATOR 


CONNECTING   NUT^ 
CYLINDER   VALVE> 


ACETYLENE 
REGULATOR 


PRESSURE  GAUGE 


HANOLR. 


OUST  PLUG> 
CYLINDER  VALVE^ 


..«— "HIGH  PRESSURE  GAUGE 
^^OW  PRESSURE  GAUGE 

HANDLE 

-HOSE  CONNECTtON 
-DUST  PLUG 
-OXYGEN  HOSE 
^CUTTING  NOZZLE 


CUTTING 
BLOWPIPE 


,_^CUTTINO 
y^OXYGEN  VfkLVE 


riir^  PRE-HE  ATINO 
VJ.        oxygen  VALVE 


-ACETYLENE  VALVE 


Fig.    GS6.     Oxy-Acetylene   welding    unit. 


590  Automotive  Trade  Training 

Lighting  Blowpipe. — The  apparatus  is  now  ready  for  use,  and  the  gases  are 
further  regulated  when  necessary  by  adjusting  the  valves  on  the  blowpipe  itself. 
Open  the  acetylene  valve  entirely.  Open  the  oxygen  valve  slightly.  Then  light 
the  gases.  After  lighting  the  gases,  open  the  oxygen  valve  wide;  adjust  the 
flame  by  turning  the  acetylene  valve  to  the  right  until  a  neutral  flame  is 
produced. 

To  Shut  Off  Blowpipe. — When  the  job  is  finished  and  you  want  to  shut  off 
the  blowpipe  for  a  short  time,  release  or  turn  the  handscrew  on  both  oxygen 
and  acetylene  regulators  to  the  left  until  the  flame  on  the  blowpipe  goes  out, 
after  which  close  the  blowpipe  valves.  When  work  is  completed  for  the  day 
and  the  apparatus  is  to  be  put  away,  first  close  the  acetylene  valve,  and  the 
oxygen  valve  of  the  blowpipe  and  turn  off  the  valves  on  both  cylinders.  Then 
open  the  valves  on  the  blowpipes  until  all  the  gas  in  the  regulators  and  hose 
passes,  out  of  the  blowpipe  into  the  air,  and  turn  the  handscrew  of  both  regu- 
lators to  the  left  until  loose.  Then  disconnect  the  oxygen  and  acetylene 
regulators  from  the  cylinders.  Each  regulator  has  a  dust  plug  which  is  to  be 
put  on  its  cylinder  connection  during  all  time  the  regulators  are  not  connected 
to  the  cylinders. 

Place  the  regulators  and  blowpipes  with  wrenches,  goggles,  heads,  and  tips 
in  their  proper  place  so  that  they  will  be  safe  and  protected  from  dust,  dirt, 
and  rough  handling.  Roll  up  the  hose  and  put  it  i  i  the  case  or  tool  box  where 
it  belongs. 

PROPERTIES  OF  METALS. 

In  order  that  a  welder  may  intelligently  handle  the  work  placed  before 
him  he  must  be  able  to  immediately  establish  the  identity  of  the  metal,  recog- 
nize its  properties,  have  a  complete  knowledge  of  its  behavior  under  the 
welding  flame,  and  know  exactly  what  treatment  to  give  it. 

This  necessary  knowledge  cannot  be  acquired  within  a  short  time.  It  will 
result  only  from  experience,  careful  observation,  and  close  examination  of  the 
work  during  welding. 

Melting  Point. — The  first  property  to  be  considered,  common  to  all  metals, 
is  the  melting  point.  Autogenous  welding  is  the  joining  together  of  two  metals 
by  uniform  fusion  at  the  line  of  contact.  In  other  words,  in  order  to  secure  a 
perfect  weld  it  is  necessary  that  each  part  be  melted,  and  the  molten  metal 
allowed  to  flow  together  and  harden  in  this  state  of  mixture. 

The  melting  point  of  any  metal  is  a  definite  quantity.  If  the  temperature 
is  raised  to  a  certain  point,  fusion  or  liquefaction  of  the  metal  occurs. 

The  melting  points  of  the  principal  metals  and  alloys  are  given  in  the 
accompanying  table. 

Expansion  and  Contraction. — When  metallic  bodies  are  subjected  to  an 
increase  in  temperature  they  expand,  the  rate  of  this  expansion  being  definitely 
known  for  each  degree  of  rise  in  temperature.  When  the  temperature  is 
lowered  a  reverse  action  takes  place,  the  bodies  contract  and  the  volume  and 
linear  dimensions  decrease.  Metals  are  very  susceptible  to  this  change  in 
volume,  each  metal  having  its  own  coefficient  of  expansion,  which  varies 
materially  from  other  metals.  As  seen  from  the  table  given  here,  of  the 
metals  most  commonly  welded  aluminum  expands  the  most,  bronze  and  brass 
next,  then  copper,  steel,  and  iron.  It  will  be  seen  that  aluminum  expands  almost 
twice  as  much  as  iron  or  steel.  The  effect  of  this  expansion  and  contraction 
is  of  great  importance  to  the  welder.  The  expansion  and  contraction  of  the 
welded  piece  cannot  be  controlled  mechanically,  because  these  forces  are 
irresistible. 

In  malleable  or  ductile  pietals  the  expansion  is  liable  to  produce  warping 
or  deformation  of  the  piece,  while  in  materials  that  are  not  of  this  nature— 


Garage  Shop  Repair  Methods 


591 


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592  Automotive  Trade  Training 

brittle  materials  such  as  cast  iron — the  result  of  the  expansion  or  contraction, 
unless  properly  cared  for,  is  breakage. 

Conductivity. — The  conductivity  of  a  metal  is  its  property  of  transmitting 
heat  throughout  its  mass.  This  property  is  not  the  same  for  all  metals,  and 
varies  within  wide  limits.     It  is  commonly  called  thermal  conductivity. 

It  can  be  seen  that  if  one  metal  conducts  or  transmits  the  heat  from  the 
welding  blowpipe  throughout  its  mass  more  rapidly  than  another,  it  is  neces- 
sary that  allowance  be  made  as  to  the  method  of  handling  the  job,  the  size  of 
the  blowpipe,  and  the  nature  of  the  preheating  equipment  used. 

In  welding  metals  of  high  thermal  conductivity  it  is  necessary  to  use 
oversize  blowpipes — as  in  the  case  of  copper.  While  the  melting  point  of 
copper  is  low,  yet  the  conductivity  is  high,  and  consequently  a  blowpipe  head 
of  larger  size  than  would  be  used  on  a  similar  thickness  of  steel  must  be 
employed. 

The  conductivity  of  a  metal  will  have  a  great  bearing  on  the  correct  way 
of  considering  the  problem  of  expansion  and  contraction.  If  one  metal 
absorbs  or  leads  the  heat  away  from  the  welding  blowpipe  more  rapidly  than 
another,  the  heated  area  will  become  very  much  larger;  and  consequently  the 
expansion  and  contraction  strains  are  affected  proportionately. 

Oxidation. — Oxidation  is  the  reaction  produced  by  the  combination  of 
ctxygen  with  a  metal.  The  weld  may  become  oxidized  by  contact  with  the 
oxygen  in  the  air  and  by  the  presence  of  excess  oxygen  in  the  welding  flame. 
An  oxide  has  none  of  the  metallic  properties  of  the  metal  from  which  it  is 
formed.  When  present  in  a  weld  it  is  an  impurity,  and  it  is  therefore  very 
necessary  that  it  be  avoided  as  far  as  possible. 

Some  oxides  are  lighter  than  the  metal  itself,  while  others  are  heavier. 
Consequently,  when  a  metal  is  reduced  to  a  molten  condition  the  oxide  will 
either  float  on  the  surface  of  the  liquid  metal  or  sink  to  the  bottom  of  the  weld. 
It  can  be  seen  that  the  sinking  is  the  least  desirable,  as  the  presence  of  the 
oxide  in  the  weld  itself  is  extremely  bad. 

The  melting  point  of  oxides  is  in  some  cases  higher,  and  in  others  lower, 
than  that  of  the  original  metals.  This  point  must  be  considered  in  attempfjn.^ 
to  eliminate  oxide  from  the  weld. 

Certain  metals  when  molten  also  have  the  property  of  dissolving  a  portion 
of  the  oxide,  the  extent  of  this  solution  being  dependent  upon  the  metal  itself. 
When  this  is  the  case  the  oxide  is  retained  in  solution  until  the  metal  hardens, 
in  some  cases  separating  and  producing  a  weakened  weld,  in  others  being 
retained  permanently  in  solution  as  an  alloy. 

Oxide  may  be  dealt  with  in  two  ways.  First,  by  taking  such  means  as 
possible  to  prevent  its  formation,  by  the  use  of  a  neutral  or  reducing  flame  in 
the  blowpipe  as  required,  or  by  the  uses  of  various  cleaning  fluxes,  etc. 
Second,  by  eliminating  the  oxide  after  its  formation  with  suitable  fluxes,  which 
either  dissolve  or  float  it  off,  or  by  mechanically  removing  it  by  the  manipula- 
tion of  the  welding  rod  or  a  paddle  made  for  this  purpose. 

The  subject  of  oxidation  is  one  of  vital  importance  to  the  welder,  one  that 
he  should  study  thoroughly  in  order  to  become  familiar  with  all  its  forms.  It 
is  due  to  oxidation  that  the  great  majority  of  defective  welds  are  faulty. 

PREHEATING. 

In  autogenous  welding  it  is  essential  that  the  welding  be  preceded  by  some 
preliminary  heating  operation,  as  there  are  many  advantages  to  be  gained  by 
this  treatment. 

Preheating  is  employed  for  two  reasons:  first,  to  prevent  the  effect  of 
expansion  and  contraction;  second,  to  decrease  the  cost  of  welding  by  supply- 
ing from  a  cheaper  source  a  considerable  volume  of  the  heat  required. 


Garage  Shop  Repair  Methods 


593 


When  a  weld  is  being  done  on  a  large  casting,  it  is  entirely  too  expensive 
to  supply  the  total  amount  of  required  heat  from  the  blowpipe  alone.  To 
offset  this,  preheating  by  some  cheaper  method  is  used;  and  the  result  is 
usually  a  saving  of  from  25  to  60  per  cent  of  the  cost  of  welding.  Not  only  is 
a  great  saving  in  gases  effected,  but  it  is  possible  to  accomplish  the  welding 
ivith  greater  speed,  due  to  the  casting  being  at  a  higher  temperature  when 
ivelding  is  started. 

There  are  various  means  of  carrying  out  this  preliminary  heating.  The 
simplest,  and  one  of  the  most  used  on  light  objects,  is  that  of  utilizing  the 
secondary  or  envelope  flame  of  the  welding  blowpipe.  In  welding  thin  castings 
and  thin  sheet  metal  work,  the  secondary  flame  of  the  blowpipe  needs  to  be 
playe.d  upon  the  parts  at  the  line  of  the  weld  for  only  a  few  seconds  in  order 
that  the  pieces  attain  a  red  heat. 

If  the  article  to  be  welded  is  of  fairly  large  size  the  use  of  a  gas  or  oil 
burning  preheating  torch  is  economical.  These  preheating  torches,  however, 
limit  the  area  of  the  surface  covered.  They  are  consequently  used  more 
successfully  on  that  work  which  requires  localized  preheating.  The  flames 
produced  are  of  sufficient  temperature,  but  not  the  necessary  volume  to  evenly 
heat  the  entire  casting  of  any  great  size.  Then,  too,  the  heating  zones  of  these 
burners  vary  because  they  are  operated  with  an  air  blast  which,  unless 
unusually  well  controlled,  fluctuates  in  pressure. 

A  common  method  of  preheating  is  by  means  of  a  charcoal  or  coke  fire 
built  around  the  article  to  be  welded.  The  usual  procedure  is  to  build  a  small 
temporary  fire  brick  furnace  around  the  piece  and  then  fill  in  with  coke  or 


BUTT  WELD 


FLANGED  WELD 


EDGE  WELD 

Fig.  687. 
charcoal  loosely  set  up.     Occasionally  coke  and  charcoal  are  mixed.     This  is 
ignited  by  means  of  kerosene.     As  the  combustion  of  the  charcoal  or  coke  is 
rather  slow,  the  preheating  is  carried  out  gradually  and  evenly.     An  air  blast 
should  not  be  used. 

In  welding  large  castings  of  a  complicated  nature  it  is  necessary  that  they 
be  preheated  evenly  throughout,  and  that  the  welding  be  carried  on  while  the 
casting  is  at  a  dull  red  temperature.  It  is  impossible  to  do  this  while  gas  or 
oil  burners  are  playing  on  the  casting,  as  the  blast  of  these  blowpipes  is  such 


594  Automotive  Trade  Training 

that  it  would  seriously  interfere  with  the  working  of  the  oxy-acetylene  flame. 
Therefore,  the  most  satisfactory  way  to  accomplish  this  is  to  partly  bury  the 
casting  in  charcoal  or  coke  and  carry  on  the  work  while  it  is  buried  in  the  hot 
coals.  The  cost  of  this  method  is  less  than  that  of  any  other,  and  because  of 
its  ease  of  application  it  is  used  more  generally  by  welders. 

Where  it  is  necessary  to  preheat  many  castings  of  a  similar  nature,  such 
as  gas  engine  cylinders,  furnace  sections,  etc.,  it  is  best  that  a  permanent 
preheating  oven  or  furnace  be  installed.  These  furnaces  may  be  designed 
particularly  for  the  work  they  are  to  receive,  and  the  fuel  used  can  be  coaf, 
coke,  charcoal,  gas,  or  oil.  In  some  cases  the  furnaces  are  muffled — that  is,  the 
flame  is  not  allowed  to  play  directly  on  the  casting;  in  others  the  casting  is 
laid  directly  in  the  flame.  With  suitable  draft  controlling  arrangements  it  is 
possible  to  establish  a  fairly  constant  temperature  in  these  furnaces,  the  advan- 
tages of  which  can  be  readily  seen. 

PREPARATION  OF  WELDS. 

The  success  of  oxy-acetylene  welding  depends,  to  a  very  great  extent,  upon 
the  proper  preparation  of  the  parts  to  be  welded.  While  the  preparation  of  a  weld 
depends  very  much  upon  the  particular  location  and  condition  of  the  parts  to 
be  welded,  there  are  nevertheless  certain  general  rules  that  must  be  followed. 
The  preparation  should  be  given  as  much  consideration  by  the  welder  as  are 
the  proper  selection  of  welding  rods,  fluxes,  and  size  of  blowpipe  head.  The 
weld  that  is  not  prepared  properly  will  usually  offset  any  skill  that  the  welder 
may  have.     Careless  preparation  has  caused  many  failures. 

Bevelling. — In  making  an  autogenous  weld,  it  is  necessary  that  fusion 
penetrate  entirely  through  the  metal.  In  order  to  aid  this  the -pieces  are 
usually  champfered  or  beveled  with  an  air  hammer,  a  grinder,  or  cold  chisel. 
By  bevelling  is  meant  the  grooving  or  champfering  of  the  metal  at  the  line  of 
the  weld,  the  depth  of  this  groove  or  V  being  equivalent  to  the  thickness  of  the 
metal.  x 

Bevelling  is  not  required  on  castings  or  plates  lighter  than  %"  in  thickness 
From  ys"  to  -h"  in  thickness  a  narrow  champfer  only  is  necessary;  one  in 
which  the  angle  opening  is  90°  is  sufficient.  From  fg"  up  to  the  maximum 
thickness  weldable  by  the  oxy-acetylene  blowpipe,  an  angle  opening  of  from 
60°  to  90°  is  sufficient,  the  angle  being  dependent  somewhat  upon  the  nature  of 
the  material  and  the  location  of  the  weld. 

It  is  not  sufficient  to  merely  separate  the  edges,  because  in  this  case  the 
upper  corners  will  be  melted  down  and  will  flow  into  the  space  between  the 
pieces,  adhering  to  the  sides  rather  than  fusing  intimately.  This  does  not 
produce  a  weld  in  any  sense,  as  experience  speedily  shows. 

Under  certain  conditions  it  is  possible  to  use  an  oxygen  cutting  blowpipe 
for  bevelling.  In  case  this  is  done,  care  must  be  taken  that  all  the  oxide 
produced  on  the  surfaces  cut  by  the  blowpipe  be  removed  before  welding. 

Setting  Up  Work. — Before  starting  to  weld,  it  is  necessary  to  adjust  or 
arrange  the  parts  to  be  welded,  so  that  during  the  operation  they  remain  in 
relatively  the  same  position.  It  is  a  common  fault  of  inexperienced  welders  to 
overlook  this  important  item,  and  consequently  the  strength  of  the  weld,  as 
well  as  the  progress  of  the  work,  will  be  seriously  affected.  In  lining  up  a 
piece  it  is  essential  that  the  deviation  from  the  original  lines,  caused  by 
expansion  and  contraction,  must  be  thoroughly  understood  and  cared  for. 

In  repairing  castings  of  nonmalleable  nature,  the  adjustment  before 
welding  should  be  very  carefully  done.  This  adjusting  is  usually  carried  out 
by  means  of  straight  edges,  jig  clamps,  keys,  wedges,  and  other  devices. 


Garage  Shop  Repair  Methods 


595 


CHARACTER  OF  FLAME. 

The  combustion  of  acetylene  in  oxygen  produces  a  two-phase  flame.  The 
luminus  cone  or  jet  indicates  the  following  re-action: 

C2H.+  0.  =  2C0  +  H. 

The  oxygen  in  this  reaction  is  supplied  from  the  cylinder.  It  is  at  this 
point  that  the  endothermic  energy  of  acetylene  is  released. 

The  bushy  non-luminous  envelope  shows  this  combination: 

2H.+02=2H20 

The  oxygen  in  this  phase  is  supplied  by  the  atmosphere. 

The  character  of  the  oxy-acetylene  flame  depends  upon  the  proportion  of 
oxygen  and  acetylene  contained  in  the  mixed  gas  as  it  issues  from  the  tip  of  the 
blowpipe.  This  proportion  is  controlled  to  some  extent  by  regulators  or 
other  devices  installed  with  the  equipment.  The  final  adjustment,  however, 
should  be  with  the  needle  valves  of  the  blowpipe.  The  proportion  of  oxygen 
is  approximately  regulated  by  adjusting  the  oxygen  regulator  to  the  proper 
pressure  as  shown  in  the  table  on  page  586.  The  acetylene  is  also  regulated 
when  using  a  medium  pressure  generator,  or  dissolved  acetylene  from  tanks, 
by  means  of  various  regulators  and  regulating  devices.  In  the  use  of  low 
pressure  and  acetylene  generators  it  is  not  necessary  to  use  devices  such  as 
this,  since  the  correct  amount  of  acetylene  is  drawn  into  the  blowpipe  by 
means  of  an  injector  in  the  welding  head  or  blowpipe. 

The  proportion  of  the  gases  may  produce  three  divisions  in  the  character 
of  the  flame — called  reducing  or  carbonizing,  neutral,  and  oxidizing.  The 
welder  should  at  all  times  observe  carefully  the  type  of  flame  produced,  and 
any  divergence  from  the  type  desired  should  be  instantly  detected  and  corrected. 

Reducing  or  Carbonizing  Flame. — When  the  blowpipe  is  first  lighted  the 
acetylene  is  greatly  in  excess.  The  flame  produced  is  of  abnormal  volume,  a 
dirty  yellow  color,  and  of  uniform  consistency.  This  is  the  reducing  type  in 
an  exaggerated   degree.     By   increasing  the   oxygen  pressure  the   size  of  the 


Fig, 


Welding  position. 


flame  is  lessened,  and  gradually  a  white  zone  of  greater  luminosity  appears 
near  the  blowpipe  tip.  This  luminous  zone  is  not  clearly  defined.  The  flame 
is  still  of  abnormal  size,  is  streaky  in  appearance,  and  a  brilliant  white.     The 


596  Automotive  Trade  Training 

extent  of  the  reducing  or  carbonizing  action  of  the  flame  is  judged  practical. y 
by  the  size  and  definition  of  the  luminous  zone.  When  the  luminous  zone 
becomes  more  clearly  defined  and  takes  the  form  and  color  of  a  bluish  white 
incandescent  cone  or  pencil,  the  streakiness  is  diminished  and  the  flame 
approaches  neutral.  The  reducing  flame  is  used  to  some  extent  on  certain  alloy 
steels,  aluminum,  and  non-ferrous  alloys. 

Neutral  or  Normal  Flame. — When  acetylene  and  oxygen  are  ignited  in  the 
correct  proportions  a  neutral  flame  is  produced.  The  appearance  of  this  flame 
is  characteristic.  It  is  made  up  of  a  distinct  and  clearly  defined  incandescent 
pencil  or  cone  of  bluish  green  in  color,  surrounded  by  a  faint  purplish  yellow 
secondary  flame  or  envelope  of  bushy  appearance.  The  incandescent  pencil  or 
cone  may  be  from  J4  "  to  5^"  in  length,  and  is  usually  rounded  or  tapered  at 
the  ends.  The  maximum  temperature  of  the  oxy-acetylene  flame  is  %"  to  ^g" 
beyond  the  extremity  of  this  jet.  In  establishing  a  neutral  flame  the  jet  should 
be  of  the  maximum  size  for  the  particular  blowpipe  head  in  use.  This  flame 
is  established  by  gradually  increasing  the  oxygen  supply  until  the  point  at 
which  the  incandescent  jet  is  of  the  greatest  clearness  is  just  passed,  and  then 
f  nally  adjusting  by  decreasing  the  oxygen  supply  until  the  desired  condition  is 
obtained. 

This  type  of  flame  is  the  one  most  extensively  used,  and  no  welder  is 
proficient  until  he  is  thoroughly  familiar  with  its  appearance  and  distinguishing 
characteristics. 

Oxidizing  Flame. — When  an  excess  of  oxygen  exists  in  the  welding  flame 
it  is  called  oxidizing.  The  effect  of  too  much  oxygen  is  to  diminish  the  size 
of  the  flame*,  blunt  or  blur  the  incandescent  cone,  and  produce  a  weak,  streaky 
or  scattering  flame.  The  oxidizing  flame  has  neither  the  size  nor  the  illumin- 
ating qualities  of  the  reducing  flame,  but"  the  incandescent  flame  is  slightly  more 
pronounced.  It  is  a  pale  violet  color.  In  some  blowpipes  the  incandescent 
cone  is  not  only  diminished  in  size,  but  is  slightly  bulged  at  its  extremity  as 
compared  to  the  normal  flame. 

It  is  rare  that  a  welder  has  occasion  to  use  this  type  of  flame,  and  hence 
he  should  be  particularly  careful  regarding  its  use. 

MANIPULATION  OF  BLOWPIPE. 

The  blowpipe  must  be  grasped  firmly  in  the  hand.  It  is  not  good  practice 
to  hold  it  in  the  fingers,  because  it  is  impossible  to  manipulate  the  flame  with  as 
great  regularity  and  control,  nor  will  it  be  possible  to  do  as  heavy  work  without 
tiring. 

Occasionally  the  hose  is  thrown  over  the  man's  shoulder.  In  this  case  the 
weight  of  the  blowpipe  is  suspended  and  held  by  the  tubing,  so  that  it  is  only 
necessary  to  impart  the  typical  welding  motion  to  the  blowpipe,  which  can 
usually  be  done  by  the  fingers.  The  movement  of  the  welding  flame  is 
hindered,  however;  and  this  method  is  therefore  not  recommended,  and  should 
be  used  only  as  a  relief  when  the  work  is  of  long  duration  and  the  operator's 
wrist  and  forearm  become  tired. 

The  head  of  the  blowpipe  should  be  inclined  at  an  angle  of  about  60°  ta 
the  plane  of  the  weld,  as  in  Fig.  688.  The  inclination  of  the  head  should  not  be 
too  great,  because  the  molten  metal  will  be  blown  ahead  of  the  welding  zone 
and  will  adhere  to  the  comparatively  cold  sides  of  the  weld.  On- the  other 
hand,  the  welding  head  should  not  be  inclined  too  near  the  vertical,  because  the 
preheating  effect  of  the  secondary  flame  will  not  be  efficiently  applied. 

There  are  certain  cases,  however,  where  the  conductivity  of  the  metal  is 
such  that  it  is  not  necessary  to  utilize  this  preheating.  Also  certain  metals 
have  the  property  of  absorbing  the  gases  of  this  flame.     Consequently,  in  these 


Garage  Shop  Repair  Methods 


597 


cases  it  is  best  that  the  flame  impingement  be  concentrated  to  as  small  an  area 
as  possible. 

The  motion  of  the  blowpipe  should  be  away  from  the  welder  and  not 
toward  him,  as  closer  observation  of  the  work  can  be  obtained  and  greater 
facility  in  making  the  weld  will  be  experienced. 

Where  thin  sheet  material  is  being  welded  and  it  is  not  necessary  to  use  a 
welding  rod  or  wire,  a  weld  may  be  produced  by  moving  the  blowpipe  in  a 
straight  line.  It  can  readily  be  seen  that  this  does  not  apply  to  welds  which 
have  been  bevelled,  and  which  require  the  use  of  filling  material,  for  in  this 
case  a  swinging  motion  must  be  imparted  to  the  blowpipe  to  take  in  both  edges 
of  the  weld  and  the  welding  wire  at  practically  the  same  time. 

In  comparatively  light  work  a  motion  is  imparted  to  the  blowpipe  which 


Fig.    689.     Blowpipe   motion. 


will  cause  the  incandescent  cone  to  describe  a  series  of  overlapping  circles,  the 
overlapping  extending  in  the  direction  of  the  welding.  In  order  that  the  weld 
be  of  good  appearance  this  must  be  constant  and  regular  in  its  advance.  The 
width  of  this  motion  is  dependent  upon  the  size  of  the  material  being  welded 
and  varies  accordingly  with  the  nature  of  the  work. 

In  heavier  work,  if  the  above  system  were  used,  a  great  deal  of  the  motion 
would  be  superfluous.  Consequently  either  an  oscillating  movement,  or  one 
in  which  the  jet  of  the  blowpipe  will  describe  semi-circles,  should  be  used  (Fig. 
689.)  This  confines  the  welding  zone;  and  while  the  progress  is  not  so  fast, 
it  is  more  thorough  than  the  other  system  for  thisclass  of  work. 

To  the  average  beginner  the  regular  control  of  these  motions  is  difficult, 
and  considerable  practice  is  required  to  become  skilled.  It  is  the  regularity  of 
these  motions  that  produces  the  characteristic  even-rippled  surface  of  good 
autogenous  welding.  The  progress  of  a  welder  and  the  quality  of  his  work  can 
be  determined  to  some  extent  by  the  skill  with  which  he  produces  this  effect. 

After  the  swinging  motions  of  the  blowpipe  have  been  mastered,  the  next 
step  will  be  to  introduce  the  welding  rod  into  the  weld  in  such  a  manner  that 
the  regular  advance  of  the  blowpipe  will  not  be  hindered  nor  retarded.  It  can 
be  seen  that  there  is  quite  a  little  attention  needed  to  secure  perfect  cooperation 
between  the  two  hands,  one  controlling  the  blowpipe  and  the  other  adding  the 
welding  rod. 

The  welding  rod  should  be  held  and  inclined  as  shown  in  Fig.  690.  In  this 
position  sufficient  quantity  of  metal  may  be  added  at  the  right  time.  With  the 
weldmg  rod  held  m  a  vertical  position  or  horizontal,  the  possibility  of  the 
addition  ot  an  excess  of  metal,  part  of  which  is  not  fused,  is  great.  In  adding 
this  metal,  care  must  be  exercised  that  the  edges  of  the  weld  are  in  the  proper 
state  of  fusion  to  receive  it.  If  the  metal  is  not  sufficiently  hot,  the  added 
material  will  merely  stick  to  the  sides  and  fusion  will  not  exist.     It  is  therefore 


598 


Automotive  Trade  Training 


necessary  that,  by  the  motion  of  the  blowpipe,  fusion  be  produced  at  the  edges 
of  the  weld  equal  with  that  of  the  welding  rod. 

The  usual  faults  of  the  beginner  are  failure  to  introduce  the  welding  rod 
at  the  proper  time  into  the  welding  zone,  to  hold  the  rod  at  the  wrong  angle,  or 
to  fuse  either  too  little  or  too  much  of  the  rod.  The  filling  material  when 
melted  should  never  be  allowed  to  fall  into  the  weld  in  drops  or  globules. 
When  the  proper  time  arrives  to  add  it,  the  welding  rod  is  lowered  into  the 
weld  until  it  is  in  contact  with  the  molten  metal  of  the  edges.  When  in  this 
position  the  flame  of  the  blowpipe  is  directed  around  it,  and  thus  fusion  is 
produced. 

It  is  customary  to  add  metal  in  excess  to  that  of  the  original  section. 

There  are  several  very  important  reasons  for  doing  this.  First,  the  weld  is 
reinforced  and  the  strength  is  accordingly  increased.  Second,  in  case  a  finished 
surface  is  desired,  a  sufficient  stock  must  remain  to  allow  for  finish.  Third, 
small  pinholes  or  blowholes  may  be  found  just  under  the  sSfface  of  the  weld, 
which  do  not  extend  to  any  depth,  and  may  be  removed  by  filing  or  machining. 


Fig. 


Welding   rod   position. 


SOURCES  OF  TROUBLE. 

The  first  source  of  trouble  in  making  a  weld  is  improper  adjustment  of  the 
welding  flame.  If  the  flame  is  not  adjusted  properly  the  resultant  weld  will  be 
inferior.  The  commonest  fault  is  the  presence  of  too  much  oxygen.  In  this 
case,  unless  the  welder  takes  a  great  deal  of  care  in  removing  the  oxide  by 
mechanical  means,  it  will  be  incorporated  throughout  the  weld.  The  presence 
of  oxide  prevents  the  thorough  blending  of  the  metal,  and  therefore  decreases 
its  strength. 

Failure  to  penetrate  to  the  bottom  of  the  weld  is  the  cause  of  a  great  many 
defects.  This  fault  is  not  only  that  of  a  beginner,  but  also  the  skilled  operator. 
Very  often  the  desire  to  complete  a  weld  rapidly  will  cause  the  operator  to 
hasten  over  the  most  important  part  of  his  work,  which  is  to  secure  the 
absolute  fusion  of  the  edges  at  the  bottom  of  the  weld,  before  the  filling  rod  is 
added.  This  defect  not  only  reduces  the  section  of  the  weld,  but  also  produces 
a  line  of  weakness  in  case  the  weld  is  submitted  to  bending  or  transverse 
strains. 

When  molten  metal  is  added  to  metal  which  is  not  in  fusion,  a  weld  is  not 


Garage  Shop  Repair  Methods  599 

secured.  The  molten  metal  merely  sticks  to  the  cooler  metal;  this  defect  is 
common  with  careless  operators.  It  may  be  caused  by  improperly  bevelling 
the  pieces  to  be  welded,  by  the  faulty  manipulation  of  the  blowpipe,  or  by 
improper  use  of  the  welding  rod. 

For  the  beginner  it  is  at  first  difficult  to  distinguish  the  proper  temperature 
at  which  to  add  the  filling  material.  Usually  he  applies  the  filling  rod  before 
the  edges  of  the  weld  are  in  fusion.  The  adhesion  in  this  case  occurs  at  both 
edges.  Occasionally  one  edge  of  the  weld  is  in  fusion,  but  the  other  is  not,  in 
which  event  the  adhesion  is  restricted  to  one  side. 

In  some  cases  the  edges  of  the  weld  are  both  at  a  point  of  fusion  too  soon. 
Under  these  conditions  a  film  of  oxide  may  exist  on  each  edge.  When  a  filling 
material  is  added,  adhesion  is  produced  with  a  film  of  oxide  separating  the 
edges  and  the  added  material.  Quite  often  an  operator  in  applying  the  welding 
rod  to  the  weld  will  concentrate  his  flame  on  the  welding  rod  and  the  edges  of 
the  weld.  As  he  plays  the  blowpipe  around  the  rod  he  will  inadvertently  force 
some  of  the  molten  metal  ahead.  The  metal  is  not  in  the  proper  state  of  fusion, 
so  there  will  consequently  be  a  small  area  of  adhesion. 

In  welding  cast  iron,  copper,  and  to  some  extent  steel,  a  very  common 
fault  of  the  beginner  is  that  of  forming  blowholes  or  porous  sections  in  the 
weld.  This  can  be  overcome  by  close  observation  of  the  work  while  welding 
and  by  certain  corrective  means,  the  principal  one  of  which  is  the  use  of  proper 
fluxes  and  proper  manipulation  of  the  welding  rod.  It  is  needless  to  say  that 
the  existence  of  this  defect  in  a  weld  seriously  affects  its  ultimate  strength. 

Occasionally  welds  are  encountered  in  which  dirt  or  some  foreign  material 
is  incorporated.  This  will  cause  porosity  and  an  inferior  weld,  which  could 
readily  have  been  avoided  by  removing  the  material  either  before  or  during 
the  execution  of  the  weld. 

STEEL. 

Steel  is  one  of  the  purest  forms  of  iron.  It  can  be  molded,  forged,  or 
drawn  to  any  desired  shape.  It  usually  contains  about  98  per  cent  or  more  of 
iron.  The  principal  constituent  of  steel,  after  iron,  is  carbon.  It  is  present 
from  almost  nothing  up  to  1.50  per  cent.  As  in  cast  iron,  the  carbon  plays  an 
important  role  in  the  properties  of  the  metal. 

Wrought  iron  is  almost  the  same  as  a  very  low  carbon  steel.  It  is  never 
cast,  but  is  always  forged.  The  process  of  its  manufacture  is  different, 
however,  in  that  it  is  finished  in  a  pasty  rather  than  liquid  condition,  and  there 
is  always  1  to  2  per  cent  of  slag  present  in  it.  From  the  standpoint  of  welding, 
it  can  be  considered  as  a  mild  steel. 

Carbon  is  dissolved  in  the  steel.  It  is  never  free  as  graphite.  The  carbon 
exerts  a  hardening  effect  on  the  metal,  which  increases  with  the  carbon  content. 
Carbon  also  increases  the  tensile  strength  up  to  about  1.30  per  cent,  where  it 
begins  to  lower  it.  The  ductility  decreases  very  rapidly  from  5  per  cent  to  15 
per  cent  carbon.     From  there  on  the  decrease  is  more  gradual. 

Silicon  has  very  little  effect  on  the  strength  of  steel.  Its  principal  property 
is  that  of  producing  soundness. 

Sulphur  lowers  the  strength  and  ductility  of  the  metal.  It  also  produces 
"red-shortness,"  which  causes  checking  during  the  working  or  casting  of  it. 

Phosphorus  produces  brittleness  and  weakens  the  metal  with  respect  to 
shock  or  vibrating  stresses.  Manganese  increases  the  tensile  strength  of  steel 
when  it  is  present  above  .4  per  cent.  Its  effect  is  dependent  upon  the  amount 
of  carbon  present. 

Oxide  of  iron  does  not  have  any  great  effect  on  the  strength  of  steel,  but 
does  affect  its  ductile  properties. 

Welding   of   Steel.— Steel   melts   at   2500-2700**.     When   molten    it    is   not 


600  Automotive  Trade  Training 

extremely  fluid.  At  dull  red  heat  it  begins  to  oxidize  rapidly.  The  oxide, 
which  melts  at  a  temperature  of  several  hundred  degrees  below  that  of  the 
metal,  remains  at  the  surface  and  can  be  easily  removed.  A  flux  is  not 
necessary.  Close  attention  must  be  paid  to  its  removal,  however,  for  its 
presence  is  very  harmful.  It  is  a  common  fault  to  have  layers  of  oxide  in  the 
weld,  which  cause  a  laminated  structure  that  weakens  the  weld  seriously. 

Steel  does  not  melt  rapidly.  It  gradually  comes  to  fusion,  confined  to 
small  areas.  Because  of  this,  the  weld  is  made  up  of  small  overlapping  layers. 
The  strength  of  the  weld  depends  greatly  on  the  thorough  bonding  of  these 
layers  to  each  other  and  to  the  bevelled  edges  of  the  piece  being  welded.  It  is 
a  common  fault  to  force  the  metal  ahead  of  the  welding  area  and  allow  it  to 
adhere  to  the  cold  sides  of  the  bevelled  edges.  This  should  be  avoided,  as  a 
weld  is  not  produced. 

A  welding  rod  of  pure  iron  wire  is  generally  used.  Occasionally  a  nickel 
steel  rod  is  used  with  good  results  on  such  work  as  crank  shafts,  etc.  A  mild 
steel  rod  is  particularly  satisfactory  on  steel  castings. 

Thickness  of  Steel                                   Diameter  of  Welding  Rod 
Vs" ^^ 

y4'  to  T^s" /s" 

J4"  to  Vs" ^s" 

Yz'  and  up %" 

Steel  is  very  sensitive  to  the  blowpipe  flame.  An  excess  of  acetylene  tends 
to  carbonize  the  metal;  an  excess  of  oxygen  tends  to  oxidize.  Therefore  a 
neutral  flame  should  always  be  used  and  should  be  tested  frequently  in  order 
that  it  be  kept  in  proper  adjustment. 

Failures  due  to  expansion  and  contraction  are  not  numerous,  because  of 
the  toughness  and  strength  of  the  metal.  If  expansion  and  contraction  are 
not  properly  taken  care  of,  however,  warping  and  buckling  will  surely  take 
place,  and  internal  strains  will  exist  in  the  weld. 

These  can  be  avoided  by  properly  setting  up  the  work  and  with  proper 
preheating  methods.  " 

The  strength  of  a  steel  weld  can  be  improved  by  mechanical  treatment. 
Hammering  is  the  most  common  method  employed.  After  the  welding  has 
been  completed,  the  entire  weld  should  be  heated  to  a  bright  red  heat,  and  the 
hammering  carried  on  at  this  temperature.  If  the  hammering  is  done  at  a 
lower  temperature,  the  weld  will  be.  weakened  instead  of  strengthened. 

CAST  IRON. 

Cast  iron  is  hard  and  brittle.  It  cannot  be  rolled.  It  is  therefore  neces- 
sary that  it  be  cast  into  the  desired  shapes.  There  are  two  general  classifica- 
tions of  commercial  cast  iron,  called  grey  iron  and  white  iron.  There  is  an  inter- 
mediate stage  known  as  "mottled"  iron.  The  difference  between  grey  and 
white  cast  is  the  nature  or  state  of  the  carbon  present.  In  grey  iron  the 
greater  portion  of  the  carbon  precipitates  as  graphite.  In  white  iron  the  major 
portion  of  the  carbon  is  combined.  The  grey  color  of  grey  iron  is  due  to  the 
precipitated  graphite.  White  iron  is  hard  and  quite  brittle.  Grey  iron  is  softer 
and  tougher. 

Cast  iron  contains  other  substances,  such  as  silicon,  sulphur,  phosphorus, 
and  manganese.  These  all  have  certain  effects  on  the  properties  of  the  iron. 
Silicon  is  used  to  soften  the  iron,  since  its  presence  aids  in  the  forming  of 
graphitic  carbon.  Manganese  has  the  reverse  effect.  When  present  in 
quantities  of  more  than  A  per  cent  it  causes  the  carbon  to  remain  in  the 
combined  state;  although  below  this  quantity  it  is  somewhat  beneficial  as  it 
counteracts    the   hardening   actions    of    sulphur.    Phosphorus    increases    the 


Garage  Shop  Repair  Methods  601 

fluidity  of  the  molten  cast  iron.  Above  one  per  cent  it  weakens  the  iron. 
Sulphur  causes  the  carbon  to  combine  with  the  iron,  thus  increasing  the 
hardness  and  the  brittleness.  It  also  has  a  weakening  effect.  It  should  never 
be  present  in  quantities  of  more  than  one  per  cent. 

Effect  of  Cooling. — When  cast  iron  is  melted  and  cooled  quickly  the  carbon 
does  not  have  a  sufficient  length  of  time  to  form  as  graphite.  It  remains  in 
the  combined  state,  which  causes  the  iron  to  have  a  low  tensile  strength,  to  be 
hard  and  brittle.  A  fracture  in  cast  iron  is  very  smooth,  close  grained,  and  of  a 
silvery  lustre,  hence  it  is  known  as  white  cast  iron.  When  cast  iron  is  cooled 
slowly,  the  carbon  will  form  graphite.  This  produces  a  large  open-grained 
iron  which  fractures  with  a  rough  granular  surface.  It  is  soft,  can  be  readily 
machined,  and  is  grey  in  color,  due  to  the  graphite  present;  hence  it  is  com- 
mercially known  as  grey  cast  iron.  Except  in  very  rare  cases  where  hardness 
is  desired  the  aim  of  the  welder  is  to  produce  grey  iron. 

Preheating. — All  cast  iron  work  should  be  preheated  to  some  extent.  The 
most  important  factor  in  the  success  of  welds  on  large  castings  is  the  proper 
treatment  by  preheating  for  expansion  and  contraction. 

In  planning  the  method  of  welding  a  large  complicated  casting  the  pre- 
heating is  always  of  primary  importance.  It  should  be  carefully  studied  from 
all  angles  and  should  be  thorough.  There  are  by  far  more  failures  in  the 
welding  of  this  metal  from  haphazard  methods  of  relieving  expansion  and 
contraction  than  from  any  other  cause. 

Welding  of  Cast  Iron. — When  cast  iron  is  in  fusion  it  oxidizes  very  rapidly. 
The  oxide  begins  to  form  at  a  bright  red  heat.  It  melts  at  a  temperature  of 
2400'-2450°  Fahrenheit.  Since  the  metal  itself  melts  at  a  temperature  300°-400'' 
F.  below  this,  it  can  be  seen  that  the  oxide  will  not  be  fused  at  the  same  time 
as  the  metal.  In  order  to  break  the  oxide  down  and  allow  the  metal  to  flow 
together  a  flux  must  be  used.  A  properly  formulated  flux  will  dissolve  the 
oxide  and  float  it  to  the  surface,  so  that  it  may  be  removed  by  scraping  the 
molten  surface  with  the  end  of  the  welding  rod.  Be  sure  to  tap  the  end 
against  something  to  free  it  from  oxide  before  continuing  to  add  it  to  the  weld. 

Cast  iron  is  quite  fluid  when  melted.  For  this  reason  it  offers  a  little 
difficulty  where  vertical  or  overhead  welding  is  attempted.  Also  its  fluidity 
causes  it  to  entrap  gases,  dirt,  and  oxide.  These  may  be  removed  by  proper 
manipulation  of  the  blowpipe  and  w.elding  rod.  The  molten  iron  can  be  forced 
ahead  of  the  weld  very  easily.  Adhesion  to  the  cold  metal  will  result,  if  the 
welding  is  not  watched  carefully. 

The  silicon  will  volatize  to  some  extent  in  the  molten  metal.  As  stated 
above,  the  lowering  of  the  amount  of  this  constituent  will  seriously  affect  the 
metal.  In  order  to  compensate  for  this  loss,  a  welding  rod  is  used  that 
contains  from  2.75  per  cent  to  3.5  per  cent  silicon.  The  other  substances  such 
as  sulphur,  manganese,  and  phosphorus  should  be  kept  within  rigid  limits.  The 
welding  rod  should  be  soundly  cast,  free  from  dirt,  sand,  scale,  rust,  etc. 

The  welding  flame  should  always  be  neutral.  The  flame  should  be  applied 
to  the  weld  at  such  an  angle  that  the  metal  will  not  be  blown  ahead.  Inasmuch 
as  the  metal  is  quite  fluid  when  molten,  the  welding  is  carried  on  in  a  series  of 
overlapping  "pools"  or  puddles.  The  welding  rod  is  applied  by  placing  it  in 
these  pools  and  playing  the  blowpipe  around  it.  The  welding  is  aided  by 
continually  "working"  the  rod  in  the  weld  in  order  that  blowholes,  dirt,  scale, 
etc.,  will  be  forced  out. 

The  central  jet  of  the  flame  should  never  impinge  on  the  molten  metal. 
It  should  be  held  ys"  to  fg"  from  it.  Occasionally  it  is  necessary  to  remove  a 
blowhole,  in  which  case  the  hole  is  burnt  out  with  the  flame  and  then  the  metal 
is  worked  over  with  the  welding  rod.'  The  working  over  of  a  weld  should  be 
avoided   unless   it   is  absolutely   necessary.     If   it   is   necessary   to    do   this   the 


602  Automotive  Trade  Training 

welding  rod  should  be  used  always,  for  otherwise  a  portion  of  the  silicon  will 
be  lost. 

When  the  weld  is  finished  and  it  is  still  hot,  the  accumulation  of  scale,  dirt, 
flux,  etc.,  on  the  surface  should  be  removed  by  scraping  with  a  coarse  file  or 
other  tool.     This  is  a  superficial  coating  that,  when  cold,  is  very  hard. 

As  soft  welds  are  nearly  always  desired,  the  castings  should  be  cooled 
slowly  and  evenly.  Where  the  work  is  complicated  or  of  heavy  section,  it  is 
by  all  means  best  to  reheat  it  to  a  good  red  heat  and  then  allow  it  to  cool. 

In  some  cases  it  is  sufficient  to  allow  the  casting  to  cool  in  the  preheating 
fire,  without  the  additional  reheating. 

MALLEABLE  IRON. 

Malleable  iron  is  a  form  of  cast  iron.  Its  principal  characteristic  as 
compared  to  grey  iron  is  its  toughness  and  ability  to  resist  shock.  It  is 
produced  by  annealing  white  iron  castings  in  pots  or  boxes,  packed  with 
hammer  and  rolling  mill  scale,  turnings,  borings,  etc.,  at  a  temperature  of  1200°- 
1300°  F.  for  48-96  hours. 

The  castings  are  then  cooled  slowly. 

During  this  annealing  process  the  material  in  which  the  castings  are  packed 
absorbs  the  carbon  from  the  surface  of  the  casting.  In  this  way  the  surface 
becomes  of  steely  nature,  while  the  interior  retains  its  cast  iron  properties.  In 
small  castings  the  decarbonization  may  exist  throughout;  in  the  larger,  a  core 
or  heart  of  cast  iron  is  always  present. 

It  can  be  readily  seen  that  a  fusion  weld  of  this  material  is  not  practical, 
because  of  the  variation  in  its  composition.  An  attempt  to  weld  it  will  produce 
a  hard,  brittle  weld,  full  of  blowholes,  and  of  very  little  strength. 

In  order  to  join  this  metal  with  the  blowpipe,  brazing  is  used.  The  metal 
is  heated  to  a  bright  red  heat,  just  below  fusion,  and  Tobin  or  manganese 
bronze  is  added  as  a  filling  material.  A  brazing  flux  is  also  used.  This  makes 
a  generally  satisfactory  joint  of  this  material. 

ALUMINUM. 

There  are  two  general  types  of  this  metal  of  interest  to  the  welder — rolled 
or  drawn  aluminum,  and  cast  aluminum.  The  commercial  rolled  metal  varies 
in  purity  from  98  per  cent  to  99.75  per  cent,  the  impurities  being  silicon  and 
iron.  Pure  aluminum  is  rarely  used  for  casting  purposes,  because  its  strength 
is  much  less  than  that  of  aluminum  alloyed  with  other  metals.  Zinc  is  the 
principal  alloying  metal,  although  small  percentages  of  copper  are  very 
frequently  used  with  it.  The  amount  of  zinc  ranges  from  5  per  cent  to  25  per 
cent,  according  to  the  requirements  of  the  casting. 

Aluminum  has  a  very  low  melting  point  as  compared  to  other  metals,  1215° 
F.  It  is  of  high  thermal  conductivity  and  has  a  high  specific  heat.  From  the 
standpoint  of  welding  its  most  important  property  is  its  combination  with 
oxygen.  Due  to  the  action  of  the  oxygen  in  the  air,  aluminum  is  always 
covered  with  a  thin  coating  of  oxide.  When  fused  a  heavy  coating  forms. 
The  oxide  is  very  refractory,  melting  at  a  temperature  above  5000°.  The 
oxide  is  also  of  a  greater  specific  gravity  than  the  molten  metal  with  the  result 
that  if  it  is  not  removed  it  will  be  distributed  throughout  the  metal. 

It  has  a  short  fusion  range,  retaining  its  normal  properties  up  to  a 
temperature  near  fusion,  when  it  becomes  pasty  and  then  passes  rapidly  into 
complete  fusion.  Oxidation  becomes  severe  just  previous  to  fusion.  The 
metal,  when  molten,  is  quite  fluid.  Gases  such  as  nitrogen,  carbon  monoxide, 
hydrogen,  etc.,  are  easily  absorbed  in  aluminum,  and  if  not  worked  out  will 
produce  blowholes  and  porosity. 


Garage  Shop  Repair  Methods 


603 


Because  of  the  rapid  fusion  and  fluidity  of  aluminum,  welding  requires  a 
little  practice  in  order  to  properly  control  it  under  the  blowpipe.  After  this 
is  done  the  welding  is  comparatively  simple. 

The  greatest  difficulty  is  that  of  removing  the  oxide.  On  sheet  aluminum 
work  a  flux  should  be  used.  The  composition  of  this  flux  is  usually  of  alkaline 
fluorides  and  chlorides.  It  is  applied  to  the  weld  by  means  of  the  welding  rod, 
or  it  is  dissolved  in  water  to  either  a  paste  or  liquid  and  applied  with  a  brush. 
This  flux  will  react  with  the  oxide  and  form  a  fusible  compound  that  will  float 
to  the  surface,  which  further  serves  as  a  protecting  coating  and  prevents 
absorption  of  gases.  The  welding  rod  should  be  as  pure  as  possible — 
particularly  free  from  certain  metals,  such  as  copper,  that  have  a  tendency  to 
set  up  a  galvanic  action  in  the  weld. 

In  preparing  the  metal  for  welding,  the  edges  to  be  welded  and  the  adjacent 
surfaces  should  be  carefully  cleaned.  In  heavier  sheets  the  edges  should  be 
bevelled.  In  the  lighter  sheets  the  welding  will  be  aided  by  flanging  them 
about  ^". 


mLYEJLEvm. 


mssLmmss 


mviJSQL 


oams  exrssuysLJ 

Fig.   691.     Section   cutting   torch. 

All  aluminum  articles  should  be  preheated  to  some  extent  before  welding. 
In  certain  cases  the  playing  of  the  secondary  flame  on  the  object  will  be 
sufficient;  in  others  a  more  thorough  treatment  is  required,  such  as  charcoal  or 
coke. 

Aluminum  castings  are  handled  a  little  differently  from  sheets  or  plates. 
As  mentioned  above,  castings  are  of  different  composition.  Since  the  metal 
has  a  low  melting  point,  high  conductivity,  and  becomes  rather  fragile  previous 
to  fusion,  preheating  and  cooling  must  be  carried  out  very  carefully.  The 
average  aluminum  casting  is  somewhat  complicated  in  its  design,  hence  the 
necessity  of  skillfulness  in  carrying  it  through  the  preliminary  heating  period. 

The  use  of  a  flux  on  castings  has  been  abandoned  by  the  majority  of 
welders.  In  place  of  it  they  break  down  and  remove  the  oxide  by  means  of  a 
paddle,  which  is  also  used  to  smooth  off  the  surface  of  the  weld  after  it  is 
completed 

When  the  weld  is  finished  the  casting  should  be  allowed  to  cool  very  slowly 
and  evenly. 


CUTTING  OF  STEEL. 

When  a  jet  of  oxygen  strikes  steel  which  has  been  previously  raised  to  a 
high  temperature,  rapid  combustion  takes  place  at  the  point  where  the  jet 
strikes  the  metal.  The  heat  generated  by  the  combustion  and  that  supplied  in 
the  preliminary  heating  is  sufficient  to  bring  the  products  of  the  combustion 
(oxides  of  iron)  to  a  molten  condition.    This  slag  flows  out,  or  is  blown  out. 


604  Automotive  Trade  Training 

of  the  cut.  After  the  reaction  is  started  it  is  carried  on  continuously  by  the 
application  of  the  heating  source  and  oxygen  jet. 

Steel  and  wrought  iron  are  the  only  metals  that  can  be  cut  economically  by 
this  process.  These  two  metals  combine  readily  with  oxygen,  with  the  libera- 
tion of  heat.  The  slag  is  produced  at  a  temperature  below  that  of  the  melting 
point  of  the  metal,  with  the  result  that  it  is  easily  separated  from  it. 

Other  metals  do  not  produce  so  much  heat  when  combining  with  oxygen, 
and  the  oxide  formed  is  not  reduced  to  a  molten  condition  at  temperatures 
below  that  of  the  metal,  with  the  result  that  it  cannot  be  easily  separated. 

The  combination  of  the  oxygen  with  the  iron  is  not  that  of  complete 
combustion.  An  examination  of  the  slag  produced  shows  the  presence  of 
metallic  iron,  which  leads  to  the  belief  that  the  oxidation  follows  the  grain 
surfaces  of  the  metal  and  more  or  less  mechanically  disintegrates  the  mass  at 
the  line  of  cutting. 

Cutting  Blowpipes. — A  cutting  blowpipe  is  used  for  applying  this  method 
of  cutting.  In  principle  the  cutting  blowpipe  differs  from  the  welding.  In 
addition  to  the  oxy-acetylene  flame  which  serves  as  a  heating  agent,  there  is  a 
separate  jet  of  pure  oxygen  for  bringing  about  combustion.  This  is  commonly 
called  the  cutting  jet.  The  oxy-acetylene  flame  is  usually  made  up  of  two  or 
more  jets,  the  size  and  position  of  which  are  regulated  with  different  nozzles 
or  tips  for  the  different  thicknesses  of  metal.  The  oxygen  for  the  oxy-acety- 
lene flame  and  that  for  the  oxygen  jet  is  controlled  by  separate  valves.  The 
cutting  jet  valve  is  usually  of  the  lever  or  plunger  type,  in  order  that  it  can  be 
conveniently  opened  and  closed. 

Fig.  691  shows  a  low  pressure  cutting  blowpipe.  It  can  be  used  with  both 
low  pressure  or  medium  pressure  acetylene  generators  or  acetylene  cylinders. 
Like  the  low  pressure  welding  blowpipe,  it  utilizes  an  injector  to  secure  the 
proper  oxygen  and  acetylene  mixture. 

Cutting  is  a  simple  operation.  There  are  four  principal  factors  to  be 
considered,  namely:  Speed  of  advance;  pressure;  volume  of  oxygen;  and 
size  of  preheating  flame.  When  the  cutting  blowpipe  is  moved  too  fast,  the 
oxygen  does  not  penetrate,  and  the  preheating  flame  does  not  have  an  oppor- 
tunity to  bring  the  metal  up  to  the  proper  temperature.  If  the  speed  is  too 
slow,  the  consumption  of  the  gases  is  too  high  and  the  cost  is  increased.  The 
blowpipe  should  be  held  steady  and  advanced  at  a  constant  rate,  in  order  that 
the  cut  may  be  smooth;  for  if  it  is  irregular  a  rough  cut  is  produced. 

In  making  a  cut  a  definite  volume  of  oxygen  is  required.  The  pressure 
of  the  oxygen  should  be  such  that  it  will  reach  the  bottom  edge  of  the  metal. 
There  are  two  ways  of  doing  this,  by  using  a  small  nozzle  and  a  higher  pressure, 
or  by  using  a  larger  nozzle  with  a  lower  pressure.  Of  the  two  the  latter  gives 
the  better  results  for  average  work. 

The  preheating  flame  should  be  of  the  proper  size.  Too  small  a  flame 
retards  the  speed  of  cutting.  Too  large  a  flame  not  only  gives  a  rough  cut. 
but  in  some  cases  hinders  the  combustion. 

JOB  240.     PRACTICAL  OXWELDING  PROBLEMS. 

Object:  Job  240  is  to  give  the  student  practice  in  the  melting  of  metal  and 
in  running  it  together.  The  student  should  light  the  blowpipe  in  accordance 
with  the  directions  given  and  establish  a  neutral  flame.  He  should  use  a  No. 
4  welding  head,  with  11  lbs.  pressure.  The  steel  should  be  set  at  an  angle  as 
shown  in  Fig.  692.  The  student  should  take  the  blowpipe  in  his  right  hand 
and  hold  the  flame  on  the  two  pieces  to  be  welded  until  the  metal  is  hot  enough 
to  run  together.  In  doing  this  job,  the  torch  should  be  held  at  an  angle  of 
about  45°.     The  tip  of  the  flame  should  be  kept  about^  }i'\irom  the  metal. 


Garage  Shop  Repair  Methods 


605 


When  the  metal  commences  to  melt,  the  blowpipe  should  be  moved  by  a 
swinging  motion  from  side  to  side,  so  as  to  melt  both  edges  together.  The 
melting  of  the  edges  of  the  two  pieces  should  be  carried  on  by  means  of  this 
swinging  motion  until  the  entire  length  of  the  joint  has  been  covered.  In 
making  this  weld,  you  should  watch  carefully  the  following  points: 

Do  not  run  the  hot  metal  on  top  of  the  cold  metal. 

Do  not  leave  any  blow  holes  nor  scale  in  the  weld. 

Do  not  hold  the  flame  on  one  side  of  the  metal  so  long  that  it  will  burn 
before  the  other  side  is  melted.  In  other  words,  keep  the  flame  moving  over 
the  pieces  to  be  welded. 

When  the  welding  has  once  started,  carry  it  on  continuously. 

Do  not  stop  and  go  back  over  your  work. 

This  problem  should  be  practiced  until  there  is  produced  a  sample  with  a 
clean,  smooth,  finished  weld. 


WELD  HERE 


STEEL 

»/8"x  2" FLAT 


FINISHED  WELD 


Fig.  692. 
JOB  241. 

The  object  of  this  job  is  to  teach  the  proper  method  of  adding  the  filling 
rod  to  the  weld. 

Take  two  %"  plates  and  bevel  them  45°.  This  can  be  done  on  an  emery 
wheel  or  with  the  cutting  blowpipe.  The  edges  to  be  welded  must  be  clean 
and  free  from  rust,  grease,  scale,  etc.  In  setting  up  the  two  plates,  butt  one 
end  of  the  two  edges  together;  spread  the  other  end  54"- 

Use  the  same  size  welding  head  and  the  same  oxygen  pressure  as  is  used 
in  Job  240.  The  filling  rod  is  used  to  fill  up  the  V  made  in  the  metal.  Care 
must  be  taken  to  see  that  the  rod  is  properly  added.  It  is  usually  a  rod  varying 
in  size  from  3/64"  to  J4"  in  diameter,  depending  on  the  size  of  the  work,  and 
30"  to  36"  long.  For  J4"  plate  a  yi"  rod  should  be  used.  The  blowpipe  should 
be  held  at  the  same  angle  as  in  Job  240.  The  filling  rod  is  held  in  the  left  hand 
and  at  about  60°  in  front  of  the  blowpipe.  The  filling  rod  should  be  held  ^" 
or  fe"  in  front  of  the  blowpipe  flame.  After  the  bevel  edges  of  the  plate  are 
brought  to  a  welding  point,  the  filling  rod  should  be  held  down  in  the  V  in  the 
molten  metal,  the  flame  being  moved  around  the  rod  and  not  on  it.  This  will 
melt  it  satisfactorily.  In  this  manner  feed  in  the  welding  rod  to  the  joint  until 
the  V  is  built  up  i^"  or  ^"  thicker  than  the  original  plates.  Proceed  in  this 
manner  until  the  joint  is  completed.  Do  not  start  to  add  the  filling  rod  until 
the  bottom  of  the  V  has  been  melted  together.  Do  not  place  the  cold  welding 
rod  into  the  molten  metal.  Always  be  sure  that  the  welding  rod  is  melted  into 
metal  that  is  already  molten.  Do  not  hold  the  end  of  the  filling  rod  above  the 
metal  and  allow  it  to  drop  into  the  weld.  Do  not  add  the  metal  from  the  filling 
rod  to  the  cold  metal  of  the  weld.  Do  not  force  the  molten  metal  ahead  on 
the  cold  sides  of  the  V.  As  in  Job  240,  both  sides  of  the  V  should  be  brought 
up  to  melting  temperature  at  the  same  time. 


606 


Automotive  Trade  Training 


WELD  HERE 


STEEL 

'/4"  PLATE 


FINISHED  WELD 


Fig.  693. 
JOB  242. 

Welding  Heavy  Steel  Plate. — Take  two  plates  1"  in  thickness  and  bevel 
one  edge  of  each  60°  on  each  side.  These  should  be  set  up  the  same  as  in  Fig. 
694,  that  is,  the  bevelled  edges  should  touch  each  other  at  one  end  and  be  %." 
apart  at  the  other. 

The  No.  15  welding  head  should  be  used  with  30  lbs.  oxygen  pressure. 
Use  yi"  diameter  welding  rod.  Proceed  from  one  side,  but  see  that  the  weld 
is  re-enfdrced  yi".  When  one  side  is  finished,  turn  the  piece  over  and  finish 
the  other.  Be  sure  that  the  bottom  of  the  V  of  the  second  side  is  thoroughly 
melted  in  order  that  it  will  meet  the  bottom  of  the  weld  of  the  other  side. 
This  point  is  very  important.  When  the  first  side  is  completed  and  turned 
over,  take  the  welding  rod  and  scrape  ofif  any  scale  that  has  been  formed  during 
the  welding.     (Sec  Fig.  694.) 


\WeLD    HERE 


STEEL 

I"  PLATE 


FINISHED  WELO 


Fig.   094. 

JOB  243. 
To  Fill  up  a  Section  of  a  Gear  or  Pinion  that  has  had  a  Tooth  or  Teeth 
Stripped. — Great  care  should  be  taken,  that  at  the  beginning  of  the  weld  the 
metal  is  melted  thoroughly  before  the  welding  rod  is  added.  It  is  necessary 
that  care  also  be  taken  that  the  shape  of  the  tooth  be  followed  as  closely  as 
possible,  in  order  that  the  least  amount  of  finish  will  be  required.  Refer  to 
Fig.  695. 

WELD    HERE  CAST  STEEL  FINISHED   WELD 


Fig.  695. 

JOB  244. 
Building  up  Lugs  and  Bosses. — Take  a  plate  of  heavy  steel  and  build  up  a 
lug  1"  high.     This  is  done  in  exactly  the  same  way  as  any  other  weld,  except 


Garage  Shop  Repair  Methods 


607 


that  care  must  be  taken  to  control  the  metal  and  not  let  it  run  over  the  plate. 
Add  the  metal  in  layers  of  Y^"  in  thickness.  Then  add  to  one  corner  of  the 
plate  a  section  of  metal  2"  x  3"  x  J^"  thick.  This  should  be  done  without 
letting  the  metal  run  over  the  edges.     (See  Fig.  696.) 

Be  sure  that  a  good  weld  is  obtained  at  the  beginning  and  that  each  layer 
is  thoroughly  welded  to  the  next.  If  a  good  weld  to  the  surface  of  the  plate 
is  not  first  obtained,  the  rest  of  the  work  is  worthless. 

Do  not  hold  the  blowpipe  too  long  in  one  place.  Keep  it  always  in  motion; 
otherwise  the  metal  will  run  down  on  the  sides.  Be  sure  that  all  scale  and 
dirt  are  worked  out  of  the  metal. 


WELD    HEPE 


STEEL 

I/2"  PLATE 


FINISHED  WELD 


Fig.  696. 


JOB  245. 

Welding  Cast  Iron. — Prepare  a  sample  with  a  45°  bevel.  Place  the  two 
beveled  edges  together.  Use  a  No.  12  head  with  the  proper  cfxygen  pressure. 
Use  Ya"  cast-iron  filling  rod. 

Cast  iron  is  always  welded  with  a  flux,  which  is  a  chemical  compound 
added  with  the  filling  rod  to  prevent  oxidation  and  to  remove  impurities.  But 
in  order  to  show  the  purpose  of  a  flux,  the  sample  should  be  welded  first 
without  it. 

The  welding  flame  should  be  pointed  the  same  as  before  in  welding  steel; 
but  after  the  metal  has  commenced  to  melt,  the  rod  should  be  put  in  the  molten 
metal  and  the  blowpipe  should  be  swung  from  one  side  of  the  V  to  the  other. 
Cast  iron  cannot  be  welded  in  layers  like  steel.  It  should  be  carried  on  in 
molten  puddles.  The  welding  rod  should  be  held  in  this  molten  metal  and 
w^orked  in  by  rubbing  the  rod  against  the  sides  of  the  V.  This  rubbing  of  the 
rod  against  the  sides  of  the  V  works  out  to  the  surface  any  sand  or  impurities 
that  may  be  in  the  metal. 

It  will  be  noted  that  the  metal  is  covered  with  a  scale  or  coating  that  is 
difficult  to  remove.     The  use  of  the  flux  will  aid  in  removing  this  coating. 

After  this  job  is  completed  another  sample  should  be  prepared  in  the  same 
way.  This  time  the  student  should  carry  on  the  welding  exactly  as  before, 
except  that  a  flux  or  scaling  powder  will  be  used.  This  application  is  made  by 
dipping  the  hot  welding  rod  into  the  flux,  a  small  quantity  of  which  will  stick 
to  the  rod.  When  the  rod  is  inserted  into  the  weld,  this  will  melt  oflF.  The 
flux  should  be  added  to  the  weld  whenever  scale  or  sand  or  dirt  appears.  Too 
much  flux  should  not  be  used  as  it  would  have  a  bad  effect  on  the  weld. 

The  rod  should  be  kept  in  motion  as  described  by  rubbing  it  along  the 
sides  of  the  weld,  and  the  weld  carried  on  with  little  puddles  of  melted  metal. 
Sand,  scale,  and  blowholes  should  be  worked  out  of  the  melted  metal  by  means 
ot  flux  and  motion  of  the  rod.  Whenever  a  white  spot  appears  in  the  melted 
metal,  it  is  either  scale  or  sand  or  some  other  impurity.  If  it  is  allowed  to 
remain  in  the  weld,  it  will  form  a  blowhole.  When  this  white  spot  is  noticed, 
it  should  be  taken  out  with  the  rod  and  removed  from  it.  Whenever  this  dirt 
is  left  on  the  rod  it  will  be  put  back  in  the  weld,  just  as  soon  as  the  rod  is 
applied  again.    Cast-iron  welding  should  be  carried  on  continuously  as  fast  as 


608 


Automotive  Trade  Training 


possible  until  the  job  Is  completed.  If  it  is  absolutely  necessary  to  go  back 
over  the  weld,  always  add  metal  from  the  filling  rod.  A  cast  iron  weld  should 
be  solid  all  the  way  through,  and  should  be  soft  so  that  it  can  be  machined. 
If  a  good  cast  iron  welding  rod  is  used,  it  will  help  the  weld  to  be  soft.  All 
cast  iron  welds  will  be  hard  if  they  are  not  cooled  slowly.  Just  after  the  weld 
has  been  finished  and  it  is  still  at  a  bright-red  heat,  scrape  off  the  surface  to 
remove  the  flux,  scale,  and  dirt  that  have  been  worked  out  of  the  metal.  If 
this  is  not  done  the  weld  will  have  a  very  hard  surface,  notwithstanding  the 
fact  that  it  might  be  soft  underneath.  This  scraping  can  be  done  by  a  chisel, 
the  blunt  end  of  a  file,  or  a  piece  of  flat  scrap  iron. 


WELD  HEPE 


CAST  IRON 


FINISHED  WELD 


Fig.  697. 

JOB  246.     WELDING  AUTOMOBILE  CYLINDERS. 

The  object  of  this  problem  is  to  give  practice  in  the  welding  of  automobile 
engine  cylinders. 

For  this  problem  a  block  of  two  cylinders  should  be  used.  The  first  break 
to  be  repaired  is  in  the  water  jacket,  as  shown  at  698A.  The  second  break  is 
en  the  flange,  as  shown  at  698B,  and  the  third  is  on  the  water  jacket,  as  shown 
at  698C.  The  fourth,  698D,  is  a  crack  on  the  head  of  the  cylinder,  extending 
from  a  spark  plug  thimble  over  the  dome  to  the  bore  of  the  cylinder.     If  any 


WELD  HEPE 


CAST  IRON 


FINISHED  WELOi 


Fig.  698A. 
WELD  HERE  CAST    IRON  FINISHED  WELD 


Fig.  698B. 


Garage  Shop  Repair  Methods  609 

WELID    HERE  CAST  IRON  FINISHED  WELD 


WELD  HEPE 


Fig.   69SC. 
CAST    IRON 


F'INISMED  WELD 


Fig.   698D. 

of  these  were  welded  cold  the  casting  would  break  from  expansion,  when  the 
flame  were  applied  to  it,  and  from  contraction  after  the  weld  had  been  made. 

In  order  to  overcome  this,  it  is  necessary  to  preheat  the  cylinder.  To  do 
this  build  a  little  furnace  around  it  by  means  of  fire  brick.  (See  Fig.  699.)  In 
order  to  give  this  lurnace  draft,  the  bottom  row  of  bricks  should  be  placed  l" 
apart.  The  cylinder  should  be  placed  on  this  little  furnace  with  the  bore  up 
and  the  head  of  the  cylinder  resting  on  two  bricks.  The  furnace  should  be  so 
built  that  there  are  6"  between  the  walls  and  the  cylinder.  There  should  be 
space  enough  to  allow  the  cylinder  to  be  turned  in  the  fire  without  knocking 
down  the  walls  of  the  furnace  when  it  is  time  to  weld.  About  three  shovels  of 
charcoal  should  be  placed  around  the  cylinder  at  first,  and  a  little  kerosene  put 
en  it  before  it  is  lighted.  After  the  charcoal  has  become  thoroughly  lighted, 
and  the  cylinder  has  become  slightly  heated,  more  charcoal  should  be  added 
until  half  the  casting  is  covered.  Then  a  piece  of  asbestos  should  be  placed 
ever  the  top  of  the  furnace  and  a  few  holes  punched  in  it  to  allow  for  draft. 
Leave  the  cylinder  in  the  furnace  until  it  is  brought  up  to  a  dark-red  heat. 
Then  turn  the  cylinder  up  so  that  the  part  to  be  welded  can  be  easily  reached. 
Then  replace  the  asbestos  sheet  and  cut  a  hole  in  it  so  that  the  cylinder  can  be 


CASTING 


ASBESTOS  PAPER 


X^<X      ^^^^rN>>^  AIR  HOLES 
Fig.   699. 


610 


Automotive  Trade  Training 


reached  by  the  blowpipe  and  rod.  The  crack  in  the  cylinder  should  have 
previously  been  chipped  out.  Weld  this  crack  exactly  as  described  before,  but 
use  a  smaller  size  welding  head — either  a  No.  6  or  No.  7.  Never  take  the 
cylinder  out  of  the  fire  to  weld  it.  Never  let  the  fire  go  out  during  the  welding. 
After  welding,  add  more  charcoal  to  bring  the  cylinder  up  to  an  even  heat,  and 
leave  it  in  the  furnace  to  cool  slowly.  Care  must  be  taken  that  the  metal  does 
not  run  through  to  settle  in  the  water  jacket.  Be  sure  to  work  out  all  dirt  or 
scale,  and  not  leave  any  pinholes  or  blowholes.  In  order  to  prevent  the  bore 
of  the  cylinder  from  scaling,  before  it  is  placed  in  the  preheating  furnace  give 
it  a  slight  coat  of  oil  and  then  apply  a  thin  coating  of  flake  graphite,  which  is 
a  form  of  carbon.  This  is  done  by  taking  the  graphite  in  the  hand  and 
throwing  it  against  the  oily  side  of  the  bore,  which  will  cause  it  to  stick.  After 
welding  is  finished,  this  can  be  cleaned  ofif  by  means  of  a  piece  of  a  rag  or  a 
piece  of  waste. 

Crack  B  can  be  welded  by  preheating  in  the  same  manner.  It  is  not 
necessary,  however,  to  preheat  it  so  much.  It  is  only  necessary  to  heat  the 
cylinder  to  a  blue  heat. 

Crack  C  should  be  welded  exactly  the  same  as  Crack  A. 

Crack  D  should  be  treated  a  little  differently,  because  the  crack  is  on  the 
inside  of  the  water  jacket.  A  portion  of  the  outer  wall,  over  the  crack,  must 
be  removed.  This  is  done  by  drilling.  The  crack  is  then  chipped  out  and 
placed  in  a  preheating  furnace,  exactly  as  described  in  A,  and  the  welding  is 
carried  on  in  the  same  manner.  When  the  weld  is  finished,  and  the  casting  is 
still  hot,  the  removed  portion  is  placed  back  into  the  outer  jacket  and  is  welded 
in.  In  order  to  hold  this  patch  in  position  while  it  is  being  welded,  a  piece  of 
cast  iron  rod  is  welded  to  it,  which  serves  as  a  handle. 

After  the  patch  has  been  welded  in,  this  rod  or  handle  can  be  cut  ofif.  The 
reheating  should  be  carried  on  as  in  Crack  A  and  the  casting  also  cooled  slowly. 

After  the  cylinder  has  been  welded  and  is  cooled  off,  it  should  be  tested  to 
be  sure  that  the  weld  is  entirely  tight.  Where  it  is  possible,  this  should  be 
tested  with  water  pressure.  If  it  is  impossible  to  do  this,  the  water  jacket 
should  be  filled  with  kerosene,  because  kerosene  penetrates  a  crack  or  a 
pinhole  faster  than  water. 

In  case  any  leaks  are  found,  the  metal  should  be  chipped  out  at  that  point, 
placed  in  the  fire,  and  rewelded  exactly  as  before. 

JOB  247. 

Building  up  of  Teeth  on  Cast  Iron  Gears  or  Pinions. — The  proper  welding 
head  and  filling  rod  should  be  selected  according  to  the  chart.  If  the  gear  is  a 
light  one — that  is,  the  face  not  more  than  three  inches  in  width  and  the  rim 
not  more  than  one  inch  in  thickness — the  job  can  be  done  without  preheating. 
Heavier  than  this  the  job  should  be  preheated. 


WELD    HERE 


CAST  IRON 


FINISHED  WELD 


Fig.   700. 


Garage  Shop  Repair  Methods  611 

The  preheating  should  be  done  with  a  charcoal  fire. 

In  doing  a  job  of  this  kind  the  greatest  care  should  be  taken  to  start  it 
properly.  The  metal  on  the  rim  of  the  gear  to  which  the  tooth  or  teeth  should 
be  added  must  be  first  melted  thoroughly.  The  welding  rod  is  then  added.  It 
is  necessary  to  control  the  metal  so  that  the  least  amount  of  machining  or 
finish  is  required;  the  tooth  can  be  built  up  by  using  carbon  blocks  that  have 
been  shaped  out  to  fit  between  the  good  teeth.  If  these  carbon  blocks  are 
shaped  and  placed  properly,  the  tooth  when  added  with  the  blowpipe  will 
require  very  little  finish  or  machining. 

Care  must  be  taken  that  the  tooth  is  built  up  fully  and  that  a  little  metal 
extends  over  each  end.  This  extra  metal  can  later  be  removed  by  filing.  To 
add  this  extra  metal  the  blowpipe  flame  should  be  held  at  the  side  of  the  tooth; 
that  is,  on  the  edge  of  the  rim  the  direction  of  the  flame  should  be  horizontal. 
This  is  to  keep  the  metal  from  running  down  on  the  side. 

In  order  that  the  tooth  may  be  machined  if  necessary  to  insure  a  finished 
product  that  will  not  be  brittle  and  crack  off  when  used,  the  weld  must  be 
cooled  slowly. 

JOB  248. 
Welding  Cast  Aluminum. — Cast  aluminum  is  usually  a  little  different  from 
sheet  aluminum,  because  it  has  zinc  and  other  metals  in  it.  A  flux  should  not 
be  used  on  cast  aluminum.  The  oxide  should  be  scraped  out  by  means  of  a 
paddle  as  the  weld  progresses.  A  paddle  such  as  used  is  made  of  a  piece  of 
one-fourth  inch  iron  rod  with  the  ends  flattened  down  so  that  it  is  about  three- 
eighths  inch  wide.     This  flat  end  should  be  ground  smooth. 

WELD   HERE  ALUMINUM  FINISHED  WELO 

CASTING 


Fig.    701. 

In  welding  an  aluminum  casting  the  flame  is  played  on  it  until  it  is  melted. 
The  metal  is  now  brought  together  by  use  of  the  paddle.  It  is  done  by  working 
the  paddle  in  the  metal  similarly  to  the  way  in  which  the  cast  iron  welding  rod 
is  used  in  working  the  impurities  out  of  a  cast-iron  weld.  The  paddle  breaks 
down  the  oxide  which  is  on  the  melted  aluminum  and  which  would  prevent  it 
from  running  together.  After  the  weld  is  started  the  paddle  is  laid  aside  and 
the  welding  rod  added.  The  entire  thickness  of  the  plate  should  not  be  filled 
up  by  means  of  the  welding  rod  at  one  operation.  After  the  V  has  been  about 
half  filled  the  welding  rod  is  laid  down  and  the  metal  worked  with  the  paddle. 
This  is  to  insure  a  proper  weld  at  the  bottom  of  the  V,  and  the  sides.  Then 
fill  up  the  weld  to  the  proper  thickness  and  smooth  off  with  the  paddle. 
Always  reinforce  the  weld  with  sufficient  metal  so  that  it  can  be  cleaned  off. 
Never  start  an  aluminum  weld,  particularly  cast  alummum,  unless  there  has 
been  a  certain  amount  of  preheating.  In  some  cases  playing  the  blowpipe  on 
both  sides  of  the  weld  will  be  sufficient;  in  others  the  preheating  must  be 
handled  more  carefully. 

JOB  249.    WELDING  AN  ALUMINUM  CRANK  CASE. 

The  object  of  this  problem  is  to  give  practice  in  the  welding  of  aluminum 
castings,  such  as  a  crank  case  as  shown.  Assume  that  there  are  three  breaks 
in  this  crank  case — A,  B,  C,  Fig.  702. 


612 


Automotive  Trade  Training 


Break  A.— This  is  a  simple  break.  The  crank  case  and  parts  to  be  welded 
are  placed  in  position  for  welding.  The  case  and  arm  should  be  lined  up  with 
straight  edges,  and  the  arm  clamped  onto  the  body  of  the  crank  case  by  means 
of  a  screw  clamp. 

The  arm  and  case  are  preheated  lightly  either  by  means  of  a  light  charcoal 
fire  or  gas  burner,  as  shown  in  the  figure.  The  bearings  of  this  crank  case  are 
usually  babbitted.  If  the  welding  is  not  too  close  to  a  bearing,  it  can  be  pro- 
tected by  inserting  wet  asbestos  in  it  and  keeping  it  wet  throughout  the  weld.  If 
the  bearing  or  bearings  are  too  close  to  the  weld,  they  should  be  removed.  The 
casting  is  preheated  until  it  begins  to  sweat,  which  is  shown  by  pimples  or 
■'bubbles"  of  metal  appearing  on  the  surface.  The  proper  preheating  tempera- 
ture can  also  be  told  by  scraping  with  the  paddle.  When  the  temperature  is 
such  that  the  metal  can  be  scraped  off  with  the  paddle  it  is  ready  to  weld. 
Select  a  proper  size  welding  head,  which  should  be  about  one  size  smaller  than 
that  used  lor  steel.  When  the  casting  is  not  pr*eheated,  which  will  rarely  be 
the  case,  the  same  size  welding  head  as  used  for  steel  should  be  used.  Use  a 
one-quarter  inch  drawn  filling  rod  in  order  to  give  good  alignment  of  the  pieces. 
They  are  not  beveled.  It  is  therefore  necessary  to  start  the  weld  by  applying 
the  flame  and  scraping  at  a  V  with  the  paddle.  The  V  is  scraped  out  as  the 
weld  progresses.  When  an  aluminum  casting  of  this  kind  is  heated  up  for 
welding  it  is  not  possible  to  turn  it,  and  it  must  remain  in  its  clamps  and  on 
straight  edges.  Vertical,  horizontal,  and  in  some  cases  overhead  welding, 
must  therefore  be  used.  Because  of  the  difficulty  in  going  over  a  weld  in  cast 
aluminum  after  it  has  once  been  made,  the  paddle  and  flame  are  applied  to  the 
under  side  of  the  weld  from  time  to  time  as  welding  progresses — to  remove  any 
excess  metal  that  hangs  there.  The  proper  amount  of  reinforcing  must  be 
added  to  allow  for  the  usual  finish.  In  making  the  weld  the  methods  o£ 
handling  the  welding  rod,  paddle,  arid  blowpipe  should  be  employed  as 
described  in  Job  248. 

Break  B. — This  break  is  in  the  rib  supporting  the  crank  shaft  bearing.  For 
this  job  the  cr^nk  case  is  set  up  and  arranged  as  for  break  A.     A  small  pre- 


WELD    HERE 


ALUMINUM 


FINISHED  WELD 


PQEHEAl  SECTIONS  WITHIN 
OOTTEDUNE^  3 


Fig.  702. 

heating  fire  of  charcoal  is  built  around  the  casting;  during  the  preheating 
period  the  welder  must  watch  his  fire  carefully  to  see  that  the  casting  does  not 
become  overheated.  It  should  be  brought  to  the  same  temperature  as  in  break 
A.  During  the  preheating  and  welding  the  case  should  be  covered  with  asbestos 
paper  so  that  it  is  protected  from  draughts.  The  welding  should  be  done  the 
same  as  in  break  A.  In  a  break  of  this  kind  slow  and  even  cooling  is  absolutely 
necessary  and  should  be  very  carefully  carried  out.  The  casting  should  not  be 
subjected  to  any  draughts  or  any  change  in  temperature. 

Break  C. — This  break  represents  a  piece  broken  from  the  side  of  the  crank 
case.     The  crank  case  and  broken  parts  are  lined  up  as  described  for  A,  and  the 


Garage  Shop  Repair  Methods 


613 


broken  piece  fitted  into  the  hole.  A  preheating  fire  of  charcoal  is  built  and 
covers  the  area  shown.  The  same  precautions  in  preheating  should  be 
observed  as  in  A  and  B.  The  v^elding  and  cooling  is  carried  on  in  exactly  the 
same  manner. 

If  two  or  more  ribs  in  the  center  of  the  casting  similar  to  break  B  were 
broken,  it  would  be  necessary  to  reheat  the  entire  casting  and  carry  the  job  on 
as  described. 

JOB  250. 

Brazing  Malleable  Iron. — It  is  not  possible  to  weld  malleable  iron,  because 
when  it  is  melted  it  loses  its  malleable  properties.  For  this  reason  the  best 
way  to  handle  a  job  of  this  kind  is  to  braze  it.  The  parts  to  be  joined  should 
be  beveled  to  60°.  Where  it  is  possible  to  apply  a  reinforcing  to  the  joint,  it  is 
sometimes  not  necessary  to  V  it  out.  Bring  the  pieces  to  be  welded  to  a 
cherry-red  heat  by  means  of  the  welding  blowpipe.  If  the  casting  is  large, 
this  preheating  may  be  helped  by  means  of  a  light  gas  blower  or  flame.  Use  a 
^"  or  J4"  Tobin  or  manganese  bronze  welding  rod;  heat  and  dip  it  into  the 
flux,  then  add  the  flux  and  the  rod  into  the  V  as  fast  as  it  will  melt  in.  Fill  up 
the  entire  V  for  a  short  section  by  means  of  the  rod,  alternately  dipping  the 
rod  into  the  flux  before  going  ahead.  In  other  words,  do  not  run  a  thin  stream 
of  metal  in  the  bottom  of  the  V  and  go  back  over  the  weld  and  fill  up  in  that 
manner.  Always  add  metal  so  that  the  reinforcement  of  at  least  an  eighth  of 
an  inch  is  secured;  never  less  than  this.  When  the  brazing  is  finished  it  should 
be  covered  up  with  asbestos  and  allowed  to  cool  fairly  slowly.  Do  not  heat 
the  edges  of  a  malleable  casting  to  a  melting  heat;  never  get  them  above  a 
cherry  red.  Be  sure  that  enough  flux  is  applied  to  keep  the  edges  of  the  casting 
clean.     Always  use  a  good  grade  of  bronze  rod.     Soft  brass  wire  will  not  do. 


BRAZE  HEPE^ 


MALLEABLE  IRON 

BRAZING 
Wplate 


Fig.  703. 


FINISHED  BRAZING 


JOB  251. 

Brazing  a  Heavy  Steel  Part  to  a  Light  Steel  Part. — A  thin  tube  and  a 
half-inch  flange  is  a  representative  problem.  A  good  braze  will  not  only  give 
a  fillet  at  the  joint  of  the  flange  to  the  tube,  but  the  brazing  will  extend  down 
the  tube  and  give  contact  between  it  and  the  flange.  To  do  this  it  must  be 
heated  properly.  The  flange  should  be  brought  to  a  red  heat  by  means  of  the 
blowpipe.  The  blowpipe  should  be  applied  to  the  flange  only  during  this 
operation.  It  is  not  necessary  to  direct  it  to  the  tube.  After  the  flange  has 
reached  a  good  red  heat,  add  flux  and  brazing  wire.  Always  be  sure  to  use 
plenty  of  flux,  as  it  is  necessary  that  both  parts  must  be  kept  clean  during  the 
brazing. 


BRAZE  HERE 


STEEL 

BRAZING 
5T.  TUBING 


Fig.   704. 


FINISHED  BRAZING 


614 


Automotive  Trade  Training 


OXY-ACETYLENE  CUTTING. 

Connecting  the  Cutting  Blowpipe. — The  cutting  blowpipe  is  connected 
exactly  the  same  as  the  welding  blowpipe^  the  only  difference  in  the  apparatus 
being  that  a  heavier  regulator  for  the  oxygen  cylinder  is  used  and  the  hose 
from  this  regulator  to  the  blowpipe  is  heavier.  This  is  because  a  heavier 
pressure  is  usually  employed  in  cutting.  This  refers  only  to  the  oxygen 
pressure,  however,  because  the  acetylene  pressure  is  never  higher  than  in 
welding. 

After  the  apparatus  is  connected  exactly  in  the  same  method  and  in  the 
same  order  as  the  welding  blowpipe,  the  oxygen  cylinder  valve  and  the  acety- 
lene cylinder  valve  are  opened.  Refer  to  the  table  on  this  page  for  the  proper 
oxygen  pressure  to  be  used  for  the  particular  thickness  of  steel  to  be  cut. 
Then  establish  this  pressure  with  the  cutting  valve  open.  Be  sure  not  to 
adjust  this  pressure  with  the  cutting  valve  closed. 

The  cutting  blowpipe  is  made  a  little  different  from  the  welding  blowpipe, 
there  being  several  holes  surrounding  a  larger  central  hole  in  the  nozzle. 
From  the  smaller  holes  issues  an  oxy-acetylene  flame  that  is  used  for  preheat- 
ing. From  the  central  hole  issues  a  jet  of  pure  oxygen  for  cutting.  There  are 
three  valves  on  the  blowpipe;  one  valve  controls  the  acetylene,  another  valve 
controls  the  oxygen  for  the  heating  flame  and  the  third  valve  is  used  to  control 
the  cutting  oxygen.  The  first  two  valves  are  regulated  exactly  as  welding 
blowpipe  valves,  because  they  must  produce  a  neutral  flame  in  the  preheating 
jets.  These  jets  are  used  to  heat  the  steer  so  that  the  central  jet  of  oxygen 
will  burn  through  the  steel. 

After  the  heating  flames  have  been  adjusted  with  the  cutting  oxygen  valve 
wide  open,  the  cutting  oxygen  valve  is  closed,  leaving  the  heating  flames  only 
burning.     The  student  is  now  ready  to  begin  cutting. 

CUTTING  TABLE 


Size 

of 

Nozzle 

Oxygen 
Pressure 

Per 

Hour 

Per  Linear  Foot 

Thickness 
of 

Speed 

Gas  Consumption 

Gas  Consumption 

Metal 

Lb.  Per 

Machine 

Hand 

Oxygen 

Acetylene 

Oxygen 

Acetylene 

In 

Sq.  In. 

Lin.  Ft. 

Lin.  Ft. 

Cu.  Ft. 

Cu.  Ft. 

Cu.  Ft. 

Cu.  Ft. 

^       1 

10 

120 

90 

28 

7.8 

0.31 

0.09 

No.  1 

15 

93 

74 

37 

11.3 

0.50 

0.15 

20 

81 

62 

48 

14.2 

0.67 

0.23 

iz 

25 

73 

55 

58 

16.3 

1.05 

0.30 

H. 

25 

63 

46 

80 

19.7 

1.74 

0.43 

1 

30 

57 

40 

100 

22.0 

2.50 

0.55 

No.  2 

35 

53 

36 

120 

23.6 

3.33 

0.66 

1 V^ 

40 

50 

33 

141 

25.3 

4.27 

0.77 

2 

50 

46 

29 

184 

27.7 

6.34 

0.96 

3                1 

55 

41 

24 

268 

31.9 

11.2 

1.33 

4 

No.  3 

65 

36 

20 

352 

35.6 

17.6 

1.78 

5 

75 

32 

17 

436 

38.8 

25.7 

2.28 

6 

85 

29 

15 

522 

41.5 

34.8 

2.76 

8 

95 

23 

11 

698 

46.2 

63.4 

4.2 

10 

115 

18 

8 

880 

50.3 

110.0 

6.3 

12 

No.  4 

135 

15 

6 

1080 

53.9 

180.0 

9.0 

14 

155 

12 

4H 

1290 

57.3 

287. 

12.7 

16 

Rivet 
Nozzle 

175 

40 

10 

3M 

1520 
240 

60.4 
25.0 

434. 

17.3 

JOB  252.  PRACTICAL  CUTTING  PROBLEMS. 

The  object  of  this  problem  is  to  give  practice  in  cutting  J^"  steel  plate. 
Take  a  piece  of  plate  and  draw  a  line  on  it,  which  is  to  be  followed  in  cutting. 
This  line  should  be  made  with  chalk,  soapstone,  or  center  punched  marks,  so 
that  it  will  not  burn  off. 


Garage  Shop  Repair  Methods 


615 


Place  the  preheating  flames  of  the  blowpipe,  which  has  been  lighted  in 
accordance  with  the  instructions  previously  given,  to  the  upper  edge  of  the 
plate,  at  the  point  where  the  cut  is  to  be  started.  The  preheating  flame  should 
be  so  placed  that  about  %"  of  the  metal  from  the  edge  is  heated.  This  should 
be  brought  to  a  bright-red  heat.  When  this  temperature  is  reached,  the  cutting 
jet  is  turned  on  by  means  of  the  cutting  valve.     It  will  immediately  burn  out 


Figure  705.    Cutting  blowpipe. 

the  steel,  which  will  be  shown  by  a  great  number  of  sparks  and  melted  slag 
dropping  from  the  plate.  The  blowpipe  is  then  moved  along  the  line  previously 
marked  out,  at  a  speed  which  will  allow  the  oxygen  to  burn  the  steel  out  clear 
through  along  this  line.  This  speed  will  come  by  practice.  If  the  blowpipe 
travels  too  fast,  the  metal  will  not  be  heated  fast  enough,  and  therefore  the 
oxygen  will  not  cut  it.  If  the  blowpipe  travels  too  slowly,  the  benefit  of  the 
heat  from  the  burning  metal  will  be  lost. 

After  the  cut  has  been  started,  the  preheating  flame  should  be  carried  so 
that  the  tips  of  the  flame  will  just  reach  the  plate.  After  skill  has  been  acquired, 
it  will  be  possible  to  carry  the  flame  ^"  or  ^"  from  the  plate.  The  student 
should  practice  on  the  plate  until  he  has  mastered  the  fundamental  principles  of 
cutting.  After  he  has  succeeded  in  making  a  cut,  he  should  try  to  produce  as 
smooth  and  as  fast  a  cut  as  possible.  For  smooth  cutting,  there  are  three 
points  to  be  watched.  First,  the  preheating  flame  should  be  kept  as  small  as 
possible.  Second,  the  oxygen  pressure  should  be  kept  such  that  it  will  blow  the 
slag  clear  through,  but  will  not  be  excessive.  The  speed  of  cutting  should  be 
constant  and  regular  and  should  be  as  fast  as  is  possible  for  the  oxygen  to  burrr 
the  metal  out.  If  too  large  a  preheating  flame  is  used  the  top  edges  of  the 
plate  will  be  melted  down.  Do  not  use  an  oxidizing  preheating  flame;  this  will 
also  cause  the  edges  to  oxidize  and  melt.  Do  not  hold  the  preheating  flame 
too  far  from  the  cut,  because  the  cut  will  not  be  continuous  and  the  efficiency 


CUTTING 

Fig.   706. 


616  Automotive  Trade  Training 

will  be  lowered.  If  the  preheating  flame  is  held  too  close  to  the  plate,  the 
edges  will  be  burnt.  Where  smoothness  is  necessary,  the  preheating  flame 
should  be  held  so  that  it  is  almost  vertical.  Where  speed  is  required,  the 
blowpipe  should  be  held  so  that  the  preheating  flame  will  travel  ahead.  This 
angle  should  be  60°  on  light  plate. 

In  cutting  a  plate,  the  left  hand  should  grasp  the  blowpipe  about  6"  from 
the  head.  Because  of  the  heat  that  will  be  reflected,  the  student  should  wear 
an  asbestos  glove  on  this  hand.  The  right  hand  should  grasp  the  handle  on  the 
blowpipe  so  that  the  thumb  or  finger  will  be  in  contact  with  the  cutting  valve. 
In  order  to  make  a  smooth  cut,  it  is  necessary  that  the  hand  be  steadied.  This 
is  done  by  resting  the  left  hand  on  the  plate.  The  smoothness  of  the  cut 
depends  on  the  steadiness  with  which  it  is  carried  on.  When  it  is  necessary  to 
make  a  bevel  cut,  the  same  method  is  used  as  described  above,  except  that  the 
blowpipe  is  held  so  that  a  cut  is  made  on  an  angle  to  the  surface  of  the  plate. 


INDEX 


Abbreviations  or  symbols,  268 

Acetylene,  583;  tanks,  584 

Acid  curing  solution,  541 

Adjusting  clutch  on  Ford  car,  81 

Air,  auxiliary,  245 ;  bags,  sectional,  527 ; 
air-bled  jets,  231 ;  gap,  327 ;  primary. 
245 ;  sleeve,  243 ;  sleeve  adjustments, 
243  ;  sleeve,  slow  speed  adjustments,  244  ; 
valve  adjusting,  229 ;  valve,  automatic, 
235  ;  valve,  auxiliary,  233 

Aluminum  welding.  602 ;  crank  case,  weld- 
ing, 611 

Ammeter,  471,  500 ;  installing  and  wiring, 
512 

Ampere,  266 

Angle  of  drive.  97 

Applying  new  lining  to  cone  type  clutch,  92 

Armatures,  276,  366,  384,  414 

Attaching  cables  to  brush  holders,  400 ; 
wires  to  lamp  sockets,  512 

Automatic  leaning  device,  245 

Automobile  cylinders,  welding,  608 

Axle,  full  floating,  43;  live.  40;  plain  live, 
40 ;  repair  work,  26 ;  semi-floating,  42  ; 
three-quarter  floating,   43 

>attery,  404  ;  box,  288  ;  care,  286,  293  ;  case, 
judging  value  of,  299 ;  caring  for  on 
charge.  323,  in  storage,  324 ;  charging. 
319-321;  charging  while  in  service,  296; 
construction,  288 ;  current  units,  401  ; 
discharging.  324 ;  faults,  297 ;  freezing, 
294  ;  grounded,  314  ;  ignition,  325  ;  open- 
ing for  inspection  and  repair,  300 ;  opera- 
tion of,  406;  primary,  265;  rating,  286; 
reassembling,  306 ;  secondary,  265 ;  shop 
repair  methods,  310 ;  system  faults,  de- 
tecting, 405 ;  terminal,  high  resistance, 
476 ;  tests  which  indicate  need  of  open- 
ing, 297  ;  testing,  295  ;  trickle  charge  in 
storage,  321  ;  wear,  288 

Bearings,  burned,  129 ;  main  engine,  128 ; 
scraping  in  main,  131 ;  taking  up  main, 
130 

Bevel  gear  and  pinion,  45 

Blowpipes,  connecting,  589;  cutting,  604; 
lighting,  590;  manipulation  of,  596; 
shutting  off,  590 

Borg  and  Beck  type  clutch,  adjusting,  94 

Brake,  adjusting  Packard  Twin  Six  foot, 
62 ;  Packard  Twin  Six  hand,  63 ;  equal- 
izers. 56  ;  names,  56 ;  relining,  60  ;  remov- 
ing grease  and  oil,  59  ;  shoes,  55  ;  squeak- 
ing, 61  ;  transmission,  55  ;  types  of,  54 

Braking  surface,  54 

Breaker  box  and  distributor  head  assembly, 
343 ;  contacts,  343 ;  contacts,  replace- 
ment of,  344  ;  points,  356,  367  ;  width  of, 
558 

Brazing  heavy  to  light  steel  parts,  613 

Brushes,  372 ;  four  slipring,  398 ;  fitting, 
and  sanding  commutator,  487 

Buick  Delco  ignition,   348 

Bulbs  and  sockets,  502 

Burning  connector  straps  on  batteries,  583 

Cables,  390 

Cadmium  test,  313 

Camel   l)ack,  522 

Cam  shafts,  135;  drive,  137 

Carbon,  removing  by  burning,  579 ;  scrap- 
ing out,   173 

Carbonizing  or  reducing  flame,  595 

Carburetion,  principles  of,  220 

Carburetor,  action,  249 ;  adjusting  Buick 
marvel,  237  ;  adjustment.  247,  250,  257  ; 
air  inlet,  251  ;  Ball  and  Ball  on  King 
cars,  251  ;  Buick,  236 ;  Cadillac,  245 ; 
care  of,  239,  245  ;  care  and  maintenance, 
258  ;  design,  222  ;  dismantling  for  clean- 
ing and  repairing,  248 ;  Dodge,  249 ; 
draining  and  cleaning,  251 ;  float  solder- 
ing. 578 ;  Hudson  supersix,  254 ;  jobs, 
260;    Kingston    models,    E.    &    L.,    237; 


Maxwell,  231;  Packard  twin  six,  233; 
pick  up  device,  252  ;  Pierce  Arrow,  256 ; 
plain  tube  or  compound  nozzle  type,  231 ; 
primary,  251 ;  Rayfleld,  model  LL — 3P, 
240 ;  Schebler  dash  pot  air  valve  type, 
258 ;  second  stage,  252 ;  Stromberg  type 
M  plain  tube,  246;  Tillotson,  234;  U.  S. 
A.  Standard.  245  ;  warm  air,  236 

Car  frame,  straightening,  18 

Cast  iron,  600  ;  cooling  effect  of,  601 ;  pre- 
heating, 601 ;  welding  of,  601,  607 

Cell    covers,    292 

Cell  jars,  289 

Cement,  vulcanizing,  525 

Cereal  preparations,  use  of,  208 

Charging  batteries  and  battery  charging 
equipment,   319  ;   conditions,   463 

Cincinnati  batteries,  opening  316 

Circuits,  internal,  276 ;  primary  or  low 
tension,  388,  395  ;  secondary  or  high  ten- 
sion, 388  ;  397 

Cleaning  hose,  588  ;  and  oiling  exposed  cone 
clutch,   92 ;   parts   of   compound,    303 

Jlutches.  85  ;  collar  care,  94  ;  cone,  88  ;  disk, 
90  ;  grabbing,  82  ;  grease  and  oil  soaked, 
91 ;  plate,  88  ;  slipping,  92  ;  transmissions 
and  universals,  73  ;  types  of,  87  ;  wet,  92 

Coil,  338,  348,  357,  419;  Bosch  synchron- 
ous, 401 ;  care  and  adjustment,  411 ; 
failure  to  vibrate,  411 ;  operation,  prin- 
ciple of,  408  ;  troubles,  cause  and  remedy, 
411  ;  vibrating  and  plain  coil  combined, 
404. 

Commutator,  278 

Condenser,  285,  332,  408,  415 ;  grounded, 
363;  short  circuited,  363 

Conductors,  268 

Connecticut   ignition   system.   354 

Connecting  rod  bearings,  fitting  or  taking 
up,  147  ;  scraping,  148 ;  on  Ford  engine, 
adjusting,  154 ;  straps  and  terminals,  re- 
moving, 300 

Contact  breaker,  384,  386,  415 

Contacts,  fitting  new,  358 ;  maker,  337 ; 
platinum  interrupter,  391 

Contact  points,  352,  422 ;  adjusting,  339 ; 
(relay),  care  of,  470;  in  series,  368 

Cooling,  fans,  200;   solutions,  203 

Cooling  systems,  193  ;  care,  195  ;  direct  air, 
193 ;  forced  and  pump  circulation,  195 ; 
indirect  air,  193  ;  water,  194 

Cord,  patch,  525;  tire,  full  section,  553, 
556 ;  tires,  repairing,  551 ;  tires,  retread- 
ing, 568 

Coupling,  removing,  387 

Cover  sealing,  303 

Cranking  failures,  458 ;  operation  of,  443 

Crank  case,   114 

Crank  shafts,  123 ;  polishing,  152 ;  right 
and  left-hand,  127 ;  troubles,  128 ;  types 
of,  126  ;  V  type  engines,  126 

Current,  alternating,  276;  control,  279; 
control  and  output  regulator,  444;  di- 
rect, 277;  generation,  275,  387,  414; 
measuring,  taken  by  lights,  517 

Cushion  and  tube  repair  gum,  522 

Cut-out,  relay,  440,  467 

Cutting,  blowpipe,  connecting,  614 ;  prob- 
lems, 614 

Cycles,  completed  per  minute,  112 

Cylinder,  blocks,  117  ;  care  and  repair,  120 ; 
heads,  120 ;  heads,  frozen,  123 ;  head,  re- 
moving, 166 ;  head,  replacing,  167  ;  head, 
shellacing,    168 ;   scored,   121 

Dash  pot,  230 
ash  and  tail  lamps,  495 

Dead  axle  drive,  46 

Degrees  converted  to  inches,  145 

Dies,  using,  573 

Differential  compound  wound  or  bucking 
series  field,  435 


617 


INDEX— Continued. 


Disk  or  plate  clutch,  rellning,  94 

Distributor,  389,  416;  board,  386;  head, 
358  ;   revolving,   357  ;   timing,   346 

Double  distributor,  care  and  maintenance, 
350 ;   Pierce  Arrow,  350 

Double  wire  or  insulated  return,  490 

Drag  link,  overhauling,  38 

Draining  oil  from,  Hudson  engine,  191 ; 
Packard  engine,  190 

Driving  member,  adjustable,  413 

Drum,  double  width,  55 

Dual,  coil  care  and  use,  403  ;  ignition,  Eise- 
mann,  419 ;  system  troubles,  421 ;  sys- 
tem,  wiring  the,   402 

Duplex  coil  construction,  vibrating,  408 

Dynamo,  generator,  452 ;  operation,  455 ; 
speed  and  output,  453 

Dyneto  system,  construction  and  care,  451 ; 
Franklin  car,  450 ;  operation,  450 

Economizer,  action  of,  249  ;  Stromberg,  248 

Electrolyte,  adjusting,  318 ;  determining 
strength  of,  318 ;  filling  battery  with, 
318 ;  making,  318 ;  making  and  using, 
317 

Element,  289  ;  and  electrolyte,  care  of,  303  ; 
repair  and  inspection,  309  ;  rotating,  424 

Engine,  without  coil,  operating  423  ;  crank 
case,  draining,  flushing  and  refilling,  190  ; 

Knight  type,  141 ;  operation,  106 ;  parts, 
functions  of,  114  ;  parts,  names  and  loca- 
tion of,  105 ;  power  generation,  102 ; 
removing  from  Ford  car,  154  ;  speed  gov- 
ernors, 259 ;  starting,  390,  timing,  160, 
352  ;  troubles  and  repairs,  114 ;  types  of, 
119 

Evaporating,  liquids,  220 

Excessive  backlash,  taking  out,  69 

Exhaust,  gas  jackets,  227  ;  heater,  236 

Exide  single  cover  type  covers,  removing 
and  re-sealing,  314 

Explosive  mixture,  224 

External,  brake  bands,  adjusting,  56 ;  cir- 
cuit on  Ford  ignition.  375 

Fabric,  breaks,  520 ;  tires,  preparation  of, 
543 

Fan  belts,  200  ;  adjusting,  201 ;  care,  200 

Faultfinder,  description  of,  471 ;  testing 
electric  systems,  471 

Field,  278 

Firing,  irregular,  391 

Flame,  character  of,  595 ;  neutral  or  nor- 
mal, 596 ;  oxidizing,  596 

Float,  chamber,  256 ;  needle  valve,  226 ; 
needle  valve,  regrinding,  260 ;  troubles, 
226;  valve  levels.  259 

Flux,  275,  577  ;  magnetic,  424 

Ford  axle  differential,  disassembling,  71 ; 
inspection  and  reassembly,  71 

Ford   clutch,   adjusting,    81 

Ford  rear  axle,  disassembling,  70 ;  remov- 
ing, 70 

Ford  transmission  bands,  relining,  81 ;  over- 
hauling, 83 

Forced  feed,   176 

Forge  fire,  building,  574 

Forging,   573 

Ford  front  axle,  overhauling  and  rebush- 
ing,  32  ;  front  radius  rod,  overhaul,  30 ; 
front  wheels  and  bearings,  overhaul,  32  ; 
steering  gear,  tightening,  32 ;  steering 
wheel  inspection  and  lubrication,   34 

Four  stroke  cycle,  107 

Frames  and  springs,  9 

Friction  disk  drive,  73 

Front  axle,  25 ;  castering  effect,  29 ;  cam- 
ber, 28  ;  design,  27  ;  straightening,  35  ; 
toe-in,  28 

Front  wheel,  spindle  cones  or  races,  replac- 
ing.  35  ;   testing  and   realigning,   30 

Fuel  systems,  213 ;  gravity,  213 ;  pressure 
feed,  213 ;  vacuum,  124 ;  vacuum  tank, 
215 


Fundamental  electrical  data,  262 :  princi- 
ples, 264 

Fuses,  281 

Garage  press,  use  of,  570 

Garage  shop  repair  methods,  569 

Gasoline,  level.  226;  nozzle,  adjusting,  229; 
systems,  213 

Gear,  pump,  179 ;  differential  construction, 
48;  double  reduction,  48;  ratio,  73; 
section  filling,  606 

General  information  on  the  Rayfield,  242 

Generating,  characteristics,  446 ;  method 
of,  373  ;   operation,  443 

Generation  and   power  plants,  102 

Generator  and  cut-out,  Gray  and  Davis, 
452  ;  lubrication,  452 

Generator,  generating,  479 ;  care,  470 ; 
motoring,  443 ;  output,  regulating,  431, 
461,  465  ;   Wagner,   470 

Governor,  oiling,  260 ;  speed,  regulating, 
260 

Ground,  282;  armature  on  generator,  485; 
between  primary  and  secondary  wind- 
ings, 363  ;  brush  holders,  479  ;  connection, 
high  resistance,  475  ;  in  motor  armature, 
479 ;  wiring  to  motor,  479 

Half  section,  building  up,  547 ;  tearing 
down,  546 

Hand  tools,  forging,  575 

Head   lights,   495 

Heat,  222 

High  speed,  78,  80  ;  adjusting.  241 

High  tension  current  distributing  from  a 
low  tension  magneto,  370 

Hood  and  radiator  covers,  202 

Hot  air,  regulation,  242  ;  stove,  227 

Hot  spot  manifold,  227 

Hot  water  heat,  227 

Hotchkiss  drive,  11 

Housing,    416 

Hudson  Delco  ignition,  347 

Hydrometer   reading,  295 

Idling  device,  242 

Igniter,  354 

Ignition  coil,  325  ;  assembly,  343  ;  open  cir- 
cuit in  the  primary  of,  360,  in  the  second- 
ary, 361,  with  connected  windings,  361  ; 
short  circuit  in  the  primary,  362  ;  in  the 
secondary  winding,   362  "■ 

Ignition,  Atwater  Kent,  type  CC,  337,  type 
K-2,  339 ;  battery,  operation  of,  410 ; 
cutting  out,  389 ;  dual,  371 ;  fails  sud- 
denly, 391 ;  Bosch  dual,  400,  duplex,  406, 
vibrating  duplex,  407 ;  contact  points, 
341 ;  detecting  general  trouble  in,  404 ; 
independence  of,  402 ;  North  East  for 
Dodge  cars,  Model  O,  342 ;  oiling,  341 ; 
operation,  principles  of,  339 ;  setting, 
358,  and  timing,  342  ;  switch,  dual,  371 ; 
timing,  350 ;  troubles,  390 ;  summary  of, 
392  ;   Wagner,  357 

Impeller  troubles,  199 

Impulse,  member,  413 ;  indicating  devices, 
179  ;  operation  of,  413  ;  starter,  the  Split- 
dorf,  426  ;  starter  care,  427 

Induced  current,  direction  of,  282 

Induction,  276;  coil,  principle  of,  325; 
rotors  and  pole  shoes,  382 

Injuries  and  blow-outs,  repairing,  538 

Inner  tubes,  splicing,  539 

Insulating  parts,  damaged,  391 

Internal,  expanding  brakes,  adjusting,  58 ; 
gear  drive,  47 

Interrupter,  removing,  391 

Inside  section,  551 

Jars  and  jar  covers,  judging  the  value  of, 
300 

Junction  and  fuse  boxes,  501 

Lamp,  bulb  to  check  timing,  346  ;  for  mag- 
neto lighting  systems,  506 ;  refiectors. 
polishing,  513  ;  for  service,  502  ;  with  bat- 
tery, 506 ;  with  dry  cells,  504 ;  with  stor- 
age batteries,  502 


618 


INDEX— Continued. 


Lead   burning,    581 

Lean  mixture,  224 

Lifting  engine  from  car,  569 

Light,  projection,  fundamentals  of,  507 ; 
not  operating,  513;  spot  and  search,  500 

Lighting,  cables,  splicing,  509 ;  switches, 
495 

Liquid  preparations,  use  of,  208 

Live  axle,  types  of  drive,  45 

Low  speed,  adjusting,  241 

Low  tension  magnetos,  timing  spark  on, 
370 

Lubrication,  exposed  cone  clutch,  92  ;  Ford 
steering  wheel,  34  ;  generator  and  cut-out, 
452 ;  governor,  260 ;  pump,  177 ;  spring 
shackles,  36;  starting  motor,  457:  steer- 
ing gear,  36;  Timken  front  wheel  bear- 
ings, 34 ;  troubles,  187  ;  universal  joint, 
101 

Lugs  and  bosses,  building  up,  606 

Magnetic,  lines  of  force,  265  ;  needle,  271 ; 
poles,  270 

Magnetism,  269 ;  producing,  270 ;  residual, 
270 

Magnetizing  steel  for  permanency,  273 

Magnets,  365  ;  electro,  270 ;  permanent,  272 

Magneto,  408,  419 ;  armature  type,  high 
tension,  376,  low  tension  circuit  in,  377  ; 
Bosch  duplex,  406,  D.  U.  types,  387,  high 
tension,  393,  395,  397;  care,  424,  426; 
coupling,  Splitdorf,  adjustable,  428; 
Dixie,  Aero  models,  423,  425 ;  driving, 
385 ;  G-4  Eisemann  high  tension,  414 ; 
Generator,  K-W  low  tension,  379 ;  H  or 
shuttle  type,  low  tension,  365  ;  high  fre- 
quency inductor  type,  373  ;  high  tension, 
376 ;  ignition,  364 ;  inductor  or  station- 
ary coil  type,  365 ;  inductor  type,  high 
tension,  378  ;  K-W  high  tension,  380  ;  low 
frequency  inductor  type,  371  ;  low  ten- 
sion, 364;  oiling,  386,  390,  424;  opera- 
tion on,  406  ;  operation,  principle  of,  380, 
423;  setting  the  DU  dual,  403;  setting 
the  ZR  dual,  403 ;  Simms  high  tension, 
383;  switch,  Dixie,  426;  testing,  423; 
timing,  385 ;  to  engine,  425 ;  timing  to 
motor,   417 ;   trouble,   detecting  dual,   405 

Main  engine  bearings,  fitting  or  taking  up, 
149;  scraping,  150;  or  crank  shaft  bear- 
ing fitting  on  Ford  engine,  153 

Malleable  iron.  602  ;  brazing,  613 

Material  and  construction,  131 

Maxwell  Simms  system,  462 

Metal,  bevelling,  594 ;  conductivity,  592 ; 
expansion  and  contraction,  590 ;  non- 
magnetic, 366  ;  preheating,  592  ;  proper- 
ties of,  590 

Melting  point,  590 

Mica,   undercutting,    488 

Mixture  of  gasoline,  correct,  225  ;  explosive, 
224  ;  lean,  225  ;  rich,  224 

Molecular  theory,  273 

Motometer,  Boyce,  206 

Motors,  overheated,  206 ;  armature,  open 
circuit  or  high  resistance,  473,  field,  473  ; 
cranking  operation,  458  ;  generator,  Buick 
Delco,  443 ;  charging  equipment,  321  ; 
Dodge  Northeast,  446 ;  operation,  443 ; 
single  unit,  Hudson  Delco,  458 

Neatsfoot  Oil,  91 

Non-conductors   or   insulators,   269 

Non-freezing  solutions,  203 

Non-leak  solutions,  208 

Nozzle,    226 

Ohm,  266 

Oil,  draining,  187 ;  pan,  cleaning,  191 ; 
pumps,  177  ;  wears  out,  185 

Oiling  systems,  175 ;  caring  for,  185 ;  full 
splash,   175 ;   splash  and   circulating,   175 

Open  circuit  in  armature  of  generator,  483  ; 
in  series  coil  of  relay,  487  ;  in  shunt  field 
of  generator,  483  ;  in  voltage  coil  of  relay, 
486 


Operating  as  generator,  459 

Overcharge,  correcting,   446 

Overhauling,  drag  link,  38 ;  Ford  front 
radius  rod,  30,  front  wheels  and  bearings, 
32,  transmission,  83 ;  rear  axles  of  sin- 
gle piece  housing  construction,  65 ;  and 
rebushing  Ford  front  axle,  32 ;  split 
housing  type  rear  axle,  63  ;  springs,  18  ; 
standard  selective  type  transmission,  83 ; 
universal  joints,  101  ;  water  pump,  211 

Overheated  engine,  cooling,  207  ;  causes  of, 
207  ;  filling,  207  ;  recognizing,  206 

Oxidization,  592 

Oxwelding  problems,   604 

Oxy-Acetylene,  cutting,  614 ;  •  flame,  587 ; 
welding,  583 

Oxygen,  583 

Packard  Twin  Six,  foot  brakes,  adjusting, 
62  ;   hand   brakes,  adjusting,   63 

Patches,  valve,  526 

Patching,  cold,  542 

Pierce  governor,  installing,  260 

Pin  holes  and  small  punctures,  repairing, 
528 

Pins,  metering,  230 

Pinion  gears,  adjusting,  67 

Pipe  threads,  571 

Piston  pins,  133;  bearing,  134;  bushing, 
removing  from  piston,  153 ;  clamp  type, 
removing,  153;  fit,  133  fitting  new,  172; 
securing,  133;  where  bushing  is  in  rod,, 
removing,    153 

Piston  clearance  allowance,  132 

Piston  rings,  132  ;  fitting  new,  169 

Planetary,  principle  explained,  79 ;  type 
transmission,  77 

Plates,  forming,  290 ;  frozen,  299  ;  judging 
the  value  of  negative,  299 ;  of  positive, 
299;   overheated,   298 

Plug  gap,  too  wide,  290 ;  short  circuited, 
290 

Plunger  pump,  179,  246 

Pole  shoes,  365,  383 

Power,    102,    225 

Pressure  gauge,  179 

Priming  for  starting,  241 

Progressive  drive,  73 

Pump,  drive,  199;  gear,  179;  oil,  177; 
packing,  211;  plunger  type,  179;  troubles, 
199;  types  of,  199;  vane,  178 

Push  button,  starting,  371 

Quarter  section,  building  up  and  tearing 
down,  544 

Radiator,  care,  209  ;  cleaning,  208 ;  honey- 
comb or  cellular  type,  198 ;  hose,  196 ; 
hose  care,  208  ;  leak  repairing  with  liquid 
compound,  210;  mountings,  197;  remov- 
ing, 209;  repairing,  210;  steaming,  197; 
testing,  209 ;  troubles,  199 ;  types  of, 
197;  tubular,   198. 

Radius   rods,    11 

Rating  electrical  power,  268 

Rear  axle,  bevel  and  pinion  gears,  adjust- 
ing, 67 ;  and  brakes,  40 ;  single  piece 
housing  construction,  overhauling,  65 ; 
trouble,  52 

Rear  wheels,  pulling,  66 

Regulator,  controlling  flow  of  acetylene, 
588,  of  oxygen,  588  ;  external  field,  defec- 
tive, 481 ;  mercury  tube,  481 ;  vibrating, 
482 

Relay  cut-out,  471 

Relay  trouble  tests,  485 

Removing,  transmission  bands,  81 ;  noise 
and  proper  meshing  of  teeth,  69 

Remy,  ignition,  352  ;  Oldsmobile,  465 

Repair,  fabrics,  523  ;  materials,  handling  of, 
529  ;  outer  casing,  543 

Repaired  battery  charging,  318 

Repairing,  cord  tires ;  551 ;  large  injuries 
and  blow-outs,  538  ;  pin  holes  and  small 
punctures,  538  ;  scraped  side  walls,  560 ; 
tread  cuts,  558 


619 


INDEX— Concluded 


Resistance  unit,  280,  350 

Retread,  bands,  semi-cured,  527 ;  building 
up,  563  ;  curing,  564 

Reverse,   78,  80  ;   gear,  76 

Rich  mixture,  224 

Rings,  leaic  proof,   132 

Rocicer  arms,   141 

Rod    bearings,    134 

Rubber  liose  troubles,   196 

Safety  spark  gap,  387,  389,  396,  417 

Sanding,   bruslies,   488;  commutator,   487 

Saturation,  274 

Sealing  compound,  292  ;  softening,  around 
the  covers,  301 ;  softening  method,  gas, 
flame,  302,  hot  water,  301,  steam,  302 

Sediment,   removing,   303 

Selective  drive,  73 

Separators,  291  ;  damaged,  298 

Series  field  regulator,  481 

Setting  and  timing  the  type  CC  system,  338 

Shackle  bolts,  adjusting,  15 

Short  circuit,  in  armature  of  generator, 
484  ;  between  generator  and  battery,  485  ; 
in  shunt  field  of  generator,  484 ;  in 
lighting  circuit,   516 ;   in   motor,    476 

Shunt    current    interruption    induction,    368 

Sight  feed,  179 

Silent  chain  care,   164 

Single  chain  drive,  46 

Single  jet,   233 

Single  wire  or  grounded  system,  490 

Six    cylinder    firing    order,    128 

Slip,  joint,  98  ;  unnecessary,  100  ;  rings,  367 

Slow  speed,  78,  80 

Soapstone,   527 

Solenoid,  285 

Soldering,  577 

Soldering  iron,  tinning,  578 

Spark,  advance,  automatic,  345,  417  ;  caused 
at  two  plugs,  simultaneously,  398 ;  con- 
trol, 331,  350,  416  ;  control,  manual,  346  ; 
plugs,  387,  wiring,  393;  timing,  334,  337, 
351 ;  unidirectional,  423 

Special  transmission  types,  76 

Split  housing  type  rear  axle  overhaul,  63  ; 

Spraying,  222 

Springs,  cantilever,  full  elliptic,  quarter 
elliptic,  semi-elliptic,  three-quarter  ellip- 
tic, 12 ;  clips,  tightening,  14 ;  overhaul, 
18 ;  leaves,  graphiting,  17 ;  shackles, 
lubricating,   16 

Standard  selective  type,  transmission  over- 
haul,   83 

Start,   refusal  to,   387 

Starter,  coupling,  Bosch  adjustable  impulse, 
412 ;  construction  and  design,  413 ;  care 
and  maintenance,  414  ;  generator  output, 
method  of  readjusting,   446 

Starting,  246 ;  characteristics,  446 ;  condi- 
tions, 463 ;  engine  with  Rayfield  car- 
buretor, 241 ;  duties,  division  of,  429 ; 
failure  to  operate,  472 ;  feature,  push 
button,  402  ;  lubrication,  457  ;  motor, 
470 ;  motors  and  generators,  429 ;  motor, 
two  unit  system.  Gray  and  Davis,  456 ; 
motor,  Wagner,  441  ;  switch,  442  ;  switch, 
open   circuit  or  high   resistance,   473 

Steel,  599;  cutting,  603;  steel  plates,  weld- 
ing, 606 

Steering  gears,  adjusting,  38 ;  and  front 
axles,  20 ;  lubrication,  36 ;  pinion  and 
sector,  25  ;  planetary,  20  ;  screw  and  nut, 
23 ;  worm  and  gear,  22  ;  worm  and  sec- 
tor, 23 

Steering  knuckle,  arm  design,  29 ;  body,  re- 
placing, 36 

Storage  battery,  test  to  determine  the  con- 
dition of,  310;  dry,  324;  wet,  324 

Stove  bolt  threads,  571 

Sulphation,   297 

Supplementary  springs  and  needle  valve, 
256 

Switches,  332,  402  ;  and  core,  407 ;  feature, 
automatic,  356 


Taps,  using,  572 ;  and  dies,  570 

Teeth  on  cast  iron  gears  or  pinions,  build- 
ing up,  610 

Temperature,  changes  of,  201 

Tempering  chart,   577 

Terminals,  and  poles,  282  ;  positive  and 
negative,  269;  and  straps,  292;  sweating 
or   burning  on.   511 

Test  outfit  for  reading  voltage,  312 

Thermosiphon,   194 

Thermostat   control.   202,   465 

Third  brush,  adjusting,  456;  control,  436, 
466;  regulation,  483 

Third   circle,    retreading,   564 

Thread,  depth  of.  571 

Throttle,  230,  234,  246  ;  and  controls,  251 ; 
needle  and  reed  valves,  256 

Timer,  335  ;  distributor,  329 

Timing,  and  ignition,  347 ;  contacts,  ad- 
justing, 350 ;  magneto  to  engine,  399, 
dual,  403,   DU,  392  ;   range,  389,  396 

Timken  front  wheel  bearings,  adjusting  and 
lubricating,  34 

Tires,  care,  519  ;  construction,  principles  of, 
51S;  cord,  518;  cures,  536;  fabric,  518; 
full  section,  building  up,  549,  tearing 
down,  547 ;  inflation,  520 ;  repair  ma- 
terials, 520 ;  reliners,  526 ;  retreading, 
561  ;  vulcanizing,  518 

Tool  steel,  hardening  and  tempering,  576 

Transformer  or  step-up  coils,  368 

Transmission,  care,  standard  selective  type, 
85,   overhaul,   83  ;   troubles,   77 ;   units,  73 

Tread,  cuts,  520 ;  repairing,  558 ;  gums, 
521  ;   preserving,   559 

Troubles,  due  to  loss  of  lubricating  qualit- 
ies,   187 

Tube   repairs,    536 

Tube  splice,  vulcanized,  541 

Tungar    rectifier,    323 

Two   valves   per  cylinder,   136 

Undercharge,    correcting,    446 

Universal,  fabric,  99  ;  joints,  95  ;  joint  lub- 
rication, 101  ;  joints,  mechanical  princi- 
ple of,  95  ;  joint  overhaul,  101 ;  removing 
from  axle,  70  ;  type  of,  97  ;  use  of  fault- 
finder for  testing  electric  systems,   471 

Vacuum,  222;  tank  parts,  Stewart,  217    .. 

Valves,  140 ;  air,  228  ;  choke,  228  ;  cleaning, 
158  ;  grinding,  158,  140  ;  lap,  144  ;  lifters, 
140 ;  method  of  removing,  158 ;  patches 
or  pads,  applying,  543 ;  regulator  or  re- 
ducing, 586 ;  reseating,  160 ;  stems, 
guides,  piston  rings,  cleaning  of,  189 ; 
stems,  replacing,  543  ;  tappets,  adjusting, 
155,  timing,   142 

Vane  pump,  centrifugal  or  rotating,  178 

Vaporization  and  carburetion,  222 

Venturi  tube,  225 

Vibration  coil  ignition,  334 

Vibrator,   principle   of,   334 

Volatile,  liquids,   220 

Voltmeter,   471,  501 

Volts,  266 

Vulcanization,  535 

Vulcanizing  hints,  531 

Water,  distilled,  293 ;  pump,  overhauling, 
211 

Welds,  preparation  of,  594 

Welding,  blowpipe,  586;  cast  aluminum, 
611 ;  heads,  587  ;  trouble,  sources  of,  598  ; 
unit,  connecting  and   starting  the,  588 

Wheel  bearing  cups,  replacing,  35 

Wheels,  truing  up,  519 

Willard   battery,   opening,   304 

Winding,   secondary,   395 

Wiring,  421,  495  ;  diagram,  360,  471 ;  direc- 
tions, 409 ;  and  lighting,  490 ;  to  motor, 
open  circuit,  478 ;  to  starting  motor, 
short  circuited,  477 

Work,  setting  up,  594 

Worm  and  gear,  46 

Zenith  model  L  plain  tube  compound  nozzle, 
242 


620 


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